Defer emitting InterfacesAdded signal until ready

Signed-off-by: Rashmica Gupta <rashmica.g@gmail.com>
Change-Id: I36b93db80fd6ff593288d107b06afd81dc1e2762
diff --git a/virtualSensor.cpp b/virtualSensor.cpp
index f0a456c..53325ff 100644
--- a/virtualSensor.cpp
+++ b/virtualSensor.cpp
@@ -398,6 +398,7 @@
 
                     /* Initialize unit value for virtual sensor */
                     virtualSensorPtr->ValueIface::unit(unitMap[sensorType]);
+                    virtualSensorPtr->emit_object_added();
 
                     virtualSensorsMap.emplace(std::move(name),
                                               std::move(virtualSensorPtr));