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/NetconfProxyMessage.java b/protocols/netconf/api/src/main/java/org/onosproject/netconf/NetconfProxyMessage.java
index 8ebfbe3..66a73b2 100644
--- a/protocols/netconf/api/src/main/java/org/onosproject/netconf/NetconfProxyMessage.java
+++ b/protocols/netconf/api/src/main/java/org/onosproject/netconf/NetconfProxyMessage.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2018-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.
@@ -16,6 +16,7 @@
 
 package org.onosproject.netconf;
 
+import org.onosproject.cluster.NodeId;
 import org.onosproject.net.DeviceId;
 
 import java.util.List;
@@ -57,4 +58,10 @@
      * @return arguments
      */
     List<String> arguments();
+
+    /**
+     * Returns the node id of proxymessage sender.
+     * @return NodeId
+     */
+    NodeId senderId();
 }