Fix setMetadata RPC saferphore

lib/metadata.js

@@ -144,7 +144,7 @@ var handleCommand = Meta.handleCommand = function (meta, line) {
         throw new Error("METADATA_UNSUPPORTED_COMMAND");
     }
 
-    commands[command](meta, args);
+    return commands[command](meta, args);
 };
 Meta.commands = Object.keys(commands);
 

rpc.js

@@ -394,6 +394,7 @@ var setMetadata = function (Env, data, unsafeKey, cb) {
             // if your command is valid but it didn't result in any change to the metadata,
             // call back now and don't write any "useless" line to the log
             if (!changed) {
+                g();
                 return void cb(void 0, metadata);
             }
             Env.msgStore.writeMetadata(channel, JSON.stringify(line), function (e) {