fix "openPort is not defined" error

Author: felicienfrancois

lib/proxy.js

@@ -93,7 +93,7 @@ Proxy.prototype._createHttpsServer = function (options, callback) {
   var wssServer = new WebSocket.Server({ server: httpsServer });
   wssServer.on('connection', this._onWebSocketServerConnect.bind(this, true));
   httpsServer.listen(function() {
-    if (callback) callback(openPort, httpsServer, wssServer);
+    if (callback) callback(httpsServer, wssServer);
   });
 };