Emit sensorHilChanged signal only if it was really changed

src/comm/QGCJSBSimLink.h

@@ -94,10 +94,11 @@ public slots:
     }
 
     void enableSensorHIL(bool enable) {
-        if (enable != _sensorHilEnabled)
+        if (enable != _sensorHilEnabled) {
             _sensorHilEnabled = enable;
             emit sensorHilChanged(enable);
         }
+    }
 
     void readBytes();