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/HostsListCommand.java b/cli/src/main/java/org/onlab/onos/cli/net/HostsListCommand.java
index 47aa688..c45470c 100644
--- a/cli/src/main/java/org/onlab/onos/cli/net/HostsListCommand.java
+++ b/cli/src/main/java/org/onlab/onos/cli/net/HostsListCommand.java
@@ -29,12 +29,11 @@
     };
 
     @Override
-    protected Object doExecute() throws Exception {
+    protected void execute() {
         HostService service = getService(HostService.class);
         for (Host host : getSortedHosts(service)) {
             printHost(host);
         }
-        return null;
     }
 
     /**