Fixed a number of CLI commands.
Refactored the StoreService/Manager stuff for common serializer pool.
diff --git a/cli/src/main/java/org/onlab/onos/cli/net/ClusterLinksCommand.java b/cli/src/main/java/org/onlab/onos/cli/net/ClusterLinksCommand.java
index be5105c..2bbfb46 100644
--- a/cli/src/main/java/org/onlab/onos/cli/net/ClusterLinksCommand.java
+++ b/cli/src/main/java/org/onlab/onos/cli/net/ClusterLinksCommand.java
@@ -20,7 +20,7 @@
     String id = null;
 
     @Override
-    protected Object doExecute() throws Exception {
+    protected void execute() {
         int cid = Integer.parseInt(id);
         init();
         TopologyCluster cluster = service.getCluster(topology, clusterId(cid));
@@ -31,7 +31,6 @@
                 print(linkString(link));
             }
         }
-        return null;
     }
 
 }