Fix cluster communicator serialization ex

Change-Id: I1f9acf682fe741816f3c70665ae3520619cb8907
diff --git a/app/src/main/java/org/opencord/igmpproxy/impl/IgmpStatisticsManager.java b/app/src/main/java/org/opencord/igmpproxy/impl/IgmpStatisticsManager.java
index 69ba6b6..ef932ef 100644
--- a/app/src/main/java/org/opencord/igmpproxy/impl/IgmpStatisticsManager.java
+++ b/app/src/main/java/org/opencord/igmpproxy/impl/IgmpStatisticsManager.java
@@ -93,6 +93,8 @@
     private KryoNamespace statSerializer = KryoNamespace.newBuilder()
             .register(KryoNamespaces.API)
             .register(IgmpStatistics.class)
+            .register(ClusterMessage.class)
+            .register(MessageSubject.class)
             .build();
 
     //Statistics values are valid or invalid