Change "type" constant name

Change-Id: Ia8a070d5d1937b68c0e77be3741c5d8f47748e4c
diff --git a/src/main/java/net/onrc/onos/core/topology/LinkImpl.java b/src/main/java/net/onrc/onos/core/topology/LinkImpl.java
index a573540..fce965a 100644
--- a/src/main/java/net/onrc/onos/core/topology/LinkImpl.java
+++ b/src/main/java/net/onrc/onos/core/topology/LinkImpl.java
@@ -174,6 +174,6 @@
      */
     @Override
     public String getType() {
-        return getStringAttribute(TopologyElement.TYPE, TopologyElement.TYPE_PACKET);
+        return getStringAttribute(TopologyElement.TYPE, TopologyElement.TYPE_PACKET_LAYER);
     }
 }