GossipHostStore: allow location change + update

- Actively sync with peer on anti-entropy message
  to improve convergence speed
- Timestamp not only location
- Refresh timestamp on delta update

Might fix ONOS-436

Change-Id: I271f9af04b87d78124d055e79b93413deaf1fa3c
diff --git a/core/store/dist/src/main/java/org/onosproject/store/host/impl/GossipHostStoreMessageSubjects.java b/core/store/dist/src/main/java/org/onosproject/store/host/impl/GossipHostStoreMessageSubjects.java
index 52dc31d..82c0859 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/host/impl/GossipHostStoreMessageSubjects.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/host/impl/GossipHostStoreMessageSubjects.java
@@ -20,9 +20,9 @@
 public final class GossipHostStoreMessageSubjects {
     private GossipHostStoreMessageSubjects() {}
 
-    public static final MessageSubject HOST_UPDATED
+    public static final MessageSubject HOST_UPDATED_MSG
         = new MessageSubject("peer-host-updated");
-    public static final MessageSubject HOST_REMOVED
+    public static final MessageSubject HOST_REMOVED_MSG
         = new MessageSubject("peer-host-removed");
     public static final MessageSubject HOST_ANTI_ENTROPY_ADVERTISEMENT
         = new MessageSubject("host-enti-entropy-advertisement");;