adding POLICY_REVOKE constant

src/main/java/org/wso2/carbon/device/mgt/iot/virtualfirealarm/agent/core/AgentConstants.java

@@ -63,7 +63,7 @@ public class AgentConstants {
          ---------------------------------------------------------------------------------------	*/
     public static final int DEFAULT_MQTT_RECONNECTION_INTERVAL = 2;        // time in seconds
     public static final int DEFAULT_MQTT_QUALITY_OF_SERVICE = 0;
-    public static final String MQTT_SUBSCRIBE_TOPIC = "%s/" + DEVICE_TYPE + "/%s";
+    public static final String MQTT_SUBSCRIBE_TOPIC = "%s/" + DEVICE_TYPE + "/%s/operation/#";
     public static final String MQTT_PUBLISH_TOPIC = "%s/" + DEVICE_TYPE + "/%s/temperature";
 
     /*	---------------------------------------------------------------------------------------