cluster: replace erroneous comma with semicolon

lib/cluster.js

@@ -474,7 +474,7 @@ function workerInit() {
       cluster.worker.state = 'listening';
       var address = obj.address();
       message.act = 'listening';
-      message.port = address && address.port || port,
+      message.port = address && address.port || port;
       send(message);
     });
   };