rainier: Add virtual ambient temp thresholds

The phosphor-virtual-sensor code recently started checking the values of
the upper/lower warning/critical thresholds for the virtual sensors and
prints to the journal if they are exceeded.  If the threshold values to
use aren't specified in the JSON file, it will just set them to zero so
any nonzero sensor value will trigger the trace.

So, even though code will not use the threshold values for the virtual
ambient temperature sensor, put some into the JSON anyway that should
never be exceeded to avoid these traces.  If the temperature does happen
to go outside the range of between 0 and 100, then seeing the trace may
be interesting anyway.

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: I9467ed17b3551af411c42352ebafbb10c4708041
diff --git a/recipes-phosphor/sensors/phosphor-virtual-sensor/rainier/virtual_sensor_config.json b/recipes-phosphor/sensors/phosphor-virtual-sensor/rainier/virtual_sensor_config.json
index 6458836..df51c66 100644
--- a/recipes-phosphor/sensors/phosphor-virtual-sensor/rainier/virtual_sensor_config.json
+++ b/recipes-phosphor/sensors/phosphor-virtual-sensor/rainier/virtual_sensor_config.json
@@ -5,6 +5,13 @@
             "Name": "Ambient_Virtual_Temp",
             "SensorType": "temperature"
         },
+        "Threshold" :
+        {
+            "CriticalHigh": 100,
+            "CriticalLow": 0,
+            "WarningHigh": 100,
+            "WarningLow": 0
+        },
         "Params":
         {
             "DbusParam":