externalsensor: Fix crash when sensor name contains spaces

Object paths cannot contain spaces.
To prevent crashes, use `name` instead of `sensorName` from the
EntityManager config.

Test Results:
- entity-manager test config
```
{
    "MaxValue": 255,
    "MinValue": -255.0,
    "Name": "IOB0 NIC0_OSFP_TEMP_C",
    "PowerState": "On",
    "Timeout": 10.0,
    "Type": "ExternalSensor",
    "Units": "xyz.openbmc_project.Sensor.Value.Unit.DegreesC"
},
{
    "MaxValue": 255,
    "MinValue": -255.0,
    "Name": "IOB0 NIC1_OSFP_TEMP_C",
    "PowerState": "On",
    "Timeout": 10.0,
    "Type": "ExternalSensor",
    "Units": "xyz.openbmc_project.Sensor.Value.Unit.DegreesC"
}
```
- externalsensor tree list
```
root@potin-catalina-bmc:~# busctl tree xyz.openbmc_project.ExternalSensor
└─ /xyz
  └─ /xyz/openbmc_project
    └─ /xyz/openbmc_project/sensors
      └─ /xyz/openbmc_project/sensors/temperature
        ├─ /xyz/openbmc_project/sensors/temperature/IOB0_NIC0_OSFP_TEMP_C
        └─ /xyz/openbmc_project/sensors/temperature/IOB0_NIC1_OSFP_TEMP_C
```

Change-Id: Ic49912f0cfed8c89cedaed6a612d13a636058b93
Signed-off-by: Potin Lai <potin.lai@quantatw.com>
diff --git a/src/external/ExternalSensor.cpp b/src/external/ExternalSensor.cpp
index 92f0f0f..3a6a407 100644
--- a/src/external/ExternalSensor.cpp
+++ b/src/external/ExternalSensor.cpp
@@ -47,7 +47,7 @@
     std::string objectPath = "/xyz/openbmc_project/sensors/";
     objectPath += dbusPath;
     objectPath += '/';
-    objectPath += sensorName;
+    objectPath += name;
 
     sensorInterface = objectServer.add_interface(
         objectPath, "xyz.openbmc_project.Sensor.Value");