Fixed a defect where a newly arrived instance would not be added on the client.

Change-Id: Ifb8c6489ef54476a2e4c322dbf83b15ecc178cd6
diff --git a/web/gui/src/main/java/org/onlab/onos/gui/TopologyViewMessages.java b/web/gui/src/main/java/org/onlab/onos/gui/TopologyViewMessages.java
index bfa7172..e4f0aed 100644
--- a/web/gui/src/main/java/org/onlab/onos/gui/TopologyViewMessages.java
+++ b/web/gui/src/main/java/org/onlab/onos/gui/TopologyViewMessages.java
@@ -311,7 +311,7 @@
         String type = messageType != null ? messageType :
                 ((event.type() == INSTANCE_ADDED) ? "addInstance" :
                         ((event.type() == INSTANCE_REMOVED ? "removeInstance" :
-                                "updateInstance")));
+                                "addInstance")));
         return envelope(type, 0, payload);
     }