modified LinkKey creation to follow other id objects

Change-Id: Ie70444f9069486d0251482464595f5835cf12539
diff --git a/core/store/serializers/src/test/java/org/onlab/onos/store/serializers/KryoSerializerTest.java b/core/store/serializers/src/test/java/org/onlab/onos/store/serializers/KryoSerializerTest.java
index d9157b4..58956d5 100644
--- a/core/store/serializers/src/test/java/org/onlab/onos/store/serializers/KryoSerializerTest.java
+++ b/core/store/serializers/src/test/java/org/onlab/onos/store/serializers/KryoSerializerTest.java
@@ -108,7 +108,7 @@
         testSerialized(ImmutableSet.of());
         testSerialized(IpPrefix.valueOf("192.168.0.1/24"));
         testSerialized(IpAddress.valueOf("192.168.0.1"));
-        testSerialized(new LinkKey(CP1, CP2));
+        testSerialized(LinkKey.linkKey(CP1, CP2));
         testSerialized(new NodeId("SomeNodeIdentifier"));
         testSerialized(P1);
         testSerialized(PID);