Fix a device's "lastTimeSeenTime" recording function into topology.
It was broken in the commit on bf0a87153ba6af73978c30cda31cc0fb1799b470.

Change-Id: If971c814ad93657561f3629dbd01d017178cfeba
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 d57613b..cfab0e8 100644
--- a/src/main/java/net/onrc/onos/core/topology/TopologyManager.java
+++ b/src/main/java/net/onrc/onos/core/topology/TopologyManager.java
@@ -1148,6 +1148,8 @@
             attachmentFound = true;
         }
 
+        deviceImpl.setLastSeenTime(deviceEvent.getLastSeenTime());
+
         // Update the device in the topology
         if (attachmentFound) {
             log.debug("Storing the device info into the Topology: mac {}", deviceEvent.getMac());