modified LinkKey creation to follow other id objects

Change-Id: Ie70444f9069486d0251482464595f5835cf12539
diff --git a/core/store/serializers/src/main/java/org/onlab/onos/store/serializers/LinkKeySerializer.java b/core/store/serializers/src/main/java/org/onlab/onos/store/serializers/LinkKeySerializer.java
index bafee4f..0f07133 100644
--- a/core/store/serializers/src/main/java/org/onlab/onos/store/serializers/LinkKeySerializer.java
+++ b/core/store/serializers/src/main/java/org/onlab/onos/store/serializers/LinkKeySerializer.java
@@ -31,6 +31,6 @@
     public LinkKey read(Kryo kryo, Input input, Class<LinkKey> type) {
         ConnectPoint src = (ConnectPoint) kryo.readClassAndObject(input);
         ConnectPoint dst = (ConnectPoint) kryo.readClassAndObject(input);
-        return new LinkKey(src, dst);
+        return LinkKey.linkKey(src, dst);
     }
 }