Removed TopologyEvents.timestamp field.
Right now it is not used, and its purpose is not clear.

If we need a similar field in the future, such field should be added
when it is clear its exact purpose and definition.

Change-Id: I81e3f1bd3db6fe9aebd579232cc9645af0400b05
diff --git a/src/main/java/net/onrc/onos/core/topology/TopologyManager.java b/src/main/java/net/onrc/onos/core/topology/TopologyManager.java
index aa6642c..b12bc0f 100644
--- a/src/main/java/net/onrc/onos/core/topology/TopologyManager.java
+++ b/src/main/java/net/onrc/onos/core/topology/TopologyManager.java
@@ -513,8 +513,7 @@
         //
         for (ITopologyListener listener : this.topologyListeners) {
             TopologyEvents events =
-                new TopologyEvents(lastEventTimestampEpochMs,
-                                   kryo.copy(apiAddedSwitchEvents),
+                new TopologyEvents(kryo.copy(apiAddedSwitchEvents),
                                    kryo.copy(apiRemovedSwitchEvents),
                                    kryo.copy(apiAddedPortEvents),
                                    kryo.copy(apiRemovedPortEvents),