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/DevicePortsListCommand.java b/cli/src/main/java/org/onlab/onos/cli/net/DevicePortsListCommand.java
index 8750424..9d68fb8 100644
--- a/cli/src/main/java/org/onlab/onos/cli/net/DevicePortsListCommand.java
+++ b/cli/src/main/java/org/onlab/onos/cli/net/DevicePortsListCommand.java
@@ -35,7 +35,7 @@
     };
 
     @Override
-    protected Object doExecute() throws Exception {
+    protected void execute() {
         DeviceService service = getService(DeviceService.class);
         if (uri == null) {
             for (Device device : getSortedDevices(service)) {
@@ -49,7 +49,6 @@
                 printDevice(service, device);
             }
         }
-        return null;
     }
 
     @Override