add hashCode, etc. to MessageSubject

Change-Id: I5c0185ea6bc8ab37fc5bade1c64cc30be6a79f9a
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/cluster/messaging/ClusterMessageHandler.java b/core/store/dist/src/main/java/org/onlab/onos/store/cluster/messaging/ClusterMessageHandler.java
index 7ec27ec..4dd7bc2 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/cluster/messaging/ClusterMessageHandler.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/cluster/messaging/ClusterMessageHandler.java
@@ -10,4 +10,4 @@
      * @param message cluster message.
      */
     public void handle(ClusterMessage message);
-}
\ No newline at end of file
+}