Fix the definition of LinkResourceService.
diff --git a/core/api/src/main/java/org/onlab/onos/net/resource/LinkResourceService.java b/core/api/src/main/java/org/onlab/onos/net/resource/LinkResourceService.java
index 0d59a46..d2736b6 100644
--- a/core/api/src/main/java/org/onlab/onos/net/resource/LinkResourceService.java
+++ b/core/api/src/main/java/org/onlab/onos/net/resource/LinkResourceService.java
@@ -56,5 +56,5 @@
      * @param link a target link
      * @return available resources for the target link
      */
-    LinkResource availableResources(Link link);
+    LinkResources availableResources(Link link);
 }