HazelcastLinkResourceStore: bug fix for ONOS-379

Change-Id: I783b51d4d937918c0bca9feb09d29263266145ee
diff --git a/core/store/dist/src/main/java/org/onosproject/store/resource/impl/HazelcastLinkResourceStore.java b/core/store/dist/src/main/java/org/onosproject/store/resource/impl/HazelcastLinkResourceStore.java
index 68c2cbb..1110396 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/resource/impl/HazelcastLinkResourceStore.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/resource/impl/HazelcastLinkResourceStore.java
@@ -497,7 +497,7 @@
                 return res;
             }
         }
-        return null;
+        return res;
     }
 
     @Override