Use LinkTuple as identifier.

- Use LinkTuple as Identifier for
  - Link, LinkEvent
- Register LinkTuple to KryoFactory
- Fix mocked Link to return LinkTuple

Change-Id: Ie58f31d4b2c906bc2343e2414d06190828e7e5c9
diff --git a/src/main/java/net/onrc/onos/core/util/serializers/KryoFactory.java b/src/main/java/net/onrc/onos/core/util/serializers/KryoFactory.java
index ae1fdb9..07efbbe 100644
--- a/src/main/java/net/onrc/onos/core/util/serializers/KryoFactory.java
+++ b/src/main/java/net/onrc/onos/core/util/serializers/KryoFactory.java
@@ -51,6 +51,7 @@
 import net.onrc.onos.core.util.IPv4Net;
 import net.onrc.onos.core.util.IPv6;
 import net.onrc.onos.core.util.IPv6Net;
+import net.onrc.onos.core.util.LinkTuple;
 import net.onrc.onos.core.util.PortNumber;
 import net.onrc.onos.core.util.Switch;
 import net.onrc.onos.core.util.SwitchPort;
@@ -193,6 +194,7 @@
         kryo.register(PortNumber.class);
         kryo.register(Switch.class);
         kryo.register(SwitchPort.class);
+        kryo.register(LinkTuple.class);
 
         // New data model-related classes
         kryo.register(DeviceEvent.class);