IntelCPUSensor: Fix threshold hysteresis is nan

Threshold's hysteresis is set to nan as default in constructor, the
function parseThresholdsFromAttr will forcely update threshold's
hysteresis as nan[1].

Because IntelCPUSensor will run parseThresholdsFromAttr in
IntelCPUSensor::handleResponse, this nan will not be updated by
hysteresisTrigger in function setInitialProperties[2].

When the threshold's hysteresis is always nan, the condition of
deassert will never be satisfied.

Update theshold's hysteresis to be 0 base on max/min chosed in
IntelCPUSensor[3] because the function parseThresholdsFromAttr is only
used by IntelCPUSensor for now.

Refs:
```
[1] https://github.com/openbmc/dbus-sensors/blob/master/src/Thresholds.cpp#L519
[2] https://github.com/openbmc/dbus-sensors/blob/master/src/sensor.hpp#L277
[3] https://github.com/openbmc/dbus-sensors/blob/master/src/IntelCPUSensor.cpp#L46
```

Tested:
DIMM_B0_CPU0 sensor with threshold 93/95 as UWT/UCT, respectively.
Enable flag 'insecure-sensor-override' and then set sensor value to
100 on dbus and then set sensor value to 50 on dbus.

Before change:
```
root@qbmc:~# busctl introspect xyz.openbmc_project.IntelCPUSensor /xyz/openbmc_project/sensors/temperature/DIMM_B0_CPU0
NAME                                                  TYPE      SIGNATURE RESULT/VALUE                             FLAGS
org.freedesktop.DBus.Introspectable                   interface -         -                                        -
.Introspect                                           method    -         s                                        -
org.freedesktop.DBus.Peer                             interface -         -                                        -
.GetMachineId                                         method    -         s                                        -
.Ping                                                 method    -         -                                        -
org.freedesktop.DBus.Properties                       interface -         -                                        -
.Get                                                  method    ss        v                                        -
.GetAll                                               method    s         a{sv}                                    -
.Set                                                  method    ssv       -                                        -
.PropertiesChanged                                    signal    sa{sv}as  -                                        -
xyz.openbmc_project.Association.Definitions           interface -         -                                        -
.Associations                                         property  a(sss)    1 "chassis" "all_sensors" "/xyz/openb... emits-change
xyz.openbmc_project.Sensor.Threshold.Critical         interface -         -                                        -
.CriticalAlarmHigh                                    property  b         true                                     emits-change
.CriticalAlarmLow                                     property  b         false                                    emits-change
.CriticalHigh                                         property  d         95                                       emits-change writable
.CriticalLow                                          property  d         nan                                      emits-change writable
xyz.openbmc_project.Sensor.Threshold.Warning          interface -         -                                        -
.WarningAlarmHigh                                     property  b         true                                     emits-change
.WarningAlarmLow                                      property  b         false                                    emits-change
.WarningHigh                                          property  d         93                                       emits-change writable
.WarningLow                                           property  d         nan                                      emits-change writable
xyz.openbmc_project.Sensor.Value                      interface -         -                                        -
.MaxValue                                             property  d         127                                      emits-change
.MinValue                                             property  d         -128                                     emits-change
.Unit                                                 property  s         "xyz.openbmc_project.Sensor.Value.Uni... emits-change
.Value                                                property  d         50                                       emits-change writable
xyz.openbmc_project.State.Decorator.Availability      interface -         -                                        -
.Available                                            property  b         true                                     emits-change writable
xyz.openbmc_project.State.Decorator.OperationalStatus interface -         -                                        -
.Functional                                           property  b         true                                     emits-change
```
After:
```
root@qbmc:~# busctl introspect xyz.openbmc_project.IntelCPUSensor /xyz/openbmc_project/sensors/temperature/DIMM_B0_CPU0
NAME                                                  TYPE      SIGNATURE RESULT/VALUE                             FLAGS
org.freedesktop.DBus.Introspectable                   interface -         -                                        -
.Introspect                                           method    -         s                                        -
org.freedesktop.DBus.Peer                             interface -         -                                        -
.GetMachineId                                         method    -         s                                        -
.Ping                                                 method    -         -                                        -
org.freedesktop.DBus.Properties                       interface -         -                                        -
.Get                                                  method    ss        v                                        -
.GetAll                                               method    s         a{sv}                                    -
.Set                                                  method    ssv       -                                        -
.PropertiesChanged                                    signal    sa{sv}as  -                                        -
xyz.openbmc_project.Association.Definitions           interface -         -                                        -
.Associations                                         property  a(sss)    1 "chassis" "all_sensors" "/xyz/openb... emits-change
xyz.openbmc_project.Sensor.Threshold.Critical         interface -         -                                        -
.CriticalAlarmHigh                                    property  b         false                                    emits-change
.CriticalAlarmLow                                     property  b         false                                    emits-change
.CriticalHigh                                         property  d         95                                       emits-change writable
.CriticalLow                                          property  d         nan                                      emits-change writable
xyz.openbmc_project.Sensor.Threshold.Warning          interface -         -                                        -
.WarningAlarmHigh                                     property  b         false                                    emits-change
.WarningAlarmLow                                      property  b         false                                    emits-change
.WarningHigh                                          property  d         93                                       emits-change writable
.WarningLow                                           property  d         nan                                      emits-change writable
xyz.openbmc_project.Sensor.Value                      interface -         -                                        -
.MaxValue                                             property  d         127                                      emits-change
.MinValue                                             property  d         -128                                     emits-change
.Unit                                                 property  s         "xyz.openbmc_project.Sensor.Value.Uni... emits-change
.Value                                                property  d         50                                       emits-change writable
xyz.openbmc_project.State.Decorator.Availability      interface -         -                                        -
.Available                                            property  b         true                                     emits-change writable
xyz.openbmc_project.State.Decorator.OperationalStatus interface -         -                                        -
.Functional                                           property  b         true                                     emits-change
```
and the signal "ThresholdAsserted" for deassert is triggered.

Change-Id: I107a2ac587f5791c47b9e7fd5a7c06ef4a312941
Signed-off-by: Jeff Lin <JeffLin2@quantatw.com>
diff --git a/src/Thresholds.cpp b/src/Thresholds.cpp
index 5f56ae2..b751c67 100644
--- a/src/Thresholds.cpp
+++ b/src/Thresholds.cpp
@@ -516,7 +516,7 @@
                         std::cout << "Threshold: " << attrPath << ": " << *val
                                   << "\n";
                     }
-                    thresholdVector.emplace_back(level, direction, *val);
+                    thresholdVector.emplace_back(level, direction, *val, 0);
                 }
             }
         }