Changed the how to relay proxy message within cluster

*changed the commnunication way to 'unicast' from 'sendAndReceived'

Change-Id: I0207c074fd2ab7b8378d9b4ce0cf877fc9aeab29
diff --git a/protocols/netconf/api/src/main/java/org/onosproject/netconf/NetconfController.java b/protocols/netconf/api/src/main/java/org/onosproject/netconf/NetconfController.java
index 45d81d2..daf92fa 100644
--- a/protocols/netconf/api/src/main/java/org/onosproject/netconf/NetconfController.java
+++ b/protocols/netconf/api/src/main/java/org/onosproject/netconf/NetconfController.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2015-present Open Networking Foundation
+ * Copyright 2019-present Open Networking Foundation
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,6 +17,7 @@
 package org.onosproject.netconf;
 
 import org.onlab.packet.IpAddress;
+import org.onosproject.cluster.NodeId;
 import org.onosproject.net.DeviceId;
 
 import java.util.Map;
@@ -138,4 +139,13 @@
         errorFuture.completeExceptionally(new NetconfException("Method executeAtMaster not implemented"));
         return errorFuture;
     }
+
+    /**
+     * Get a contoller node Id .
+     *
+     * @return controller node Id
+     */
+    default NodeId getLocalNodeId() {
+        return null;
+    }
 }