Change for the way to learn IP and MAC binding.
ProxyArpManager has not done unit tests because the codes will be changed soon by another Jono's fix.

Change-Id: I0cf45aa328871497db522c531dcef999156c2d55
diff --git a/src/main/java/net/onrc/onos/core/util/serializers/KryoFactory.java b/src/main/java/net/onrc/onos/core/util/serializers/KryoFactory.java
index e229d30..d1794d1 100644
--- a/src/main/java/net/onrc/onos/core/util/serializers/KryoFactory.java
+++ b/src/main/java/net/onrc/onos/core/util/serializers/KryoFactory.java
@@ -7,6 +7,7 @@
 import java.util.HashSet;
 
 import net.floodlightcontroller.util.MACAddress;
+import net.onrc.onos.apps.proxyarp.ArpCacheNotification;
 import net.onrc.onos.apps.proxyarp.ArpReplyNotification;
 import net.onrc.onos.core.devicemanager.OnosDevice;
 import net.onrc.onos.core.intent.ConstrainedShortestPathIntent;
@@ -219,6 +220,7 @@
         kryo.register(BroadcastPacketOutNotification.class);
         kryo.register(SinglePacketOutNotification.class);
         kryo.register(ArpReplyNotification.class);
+        kryo.register(ArpCacheNotification.class);
 
         return kryo;
     }