Simplified the port handling logic for VM live migration case

Change-Id: Ib28978bb2ee62c4719261c38eebb72a006f81f19
diff --git a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingIcmpHandler.java b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingIcmpHandler.java
index 292ea3f..e5289a2 100644
--- a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingIcmpHandler.java
+++ b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingIcmpHandler.java
@@ -120,7 +120,8 @@
     private static final KryoNamespace SERIALIZER_ICMP_MAP = KryoNamespace.newBuilder()
             .register(KryoNamespaces.API)
             .register(InstancePort.class)
-            .register(HostBasedInstancePort.class)
+            .register(DefaultInstancePort.class)
+            .register(InstancePort.State.class)
             .build();
 
     private ApplicationId appId;