fix a bug in finding ios real device id

lib/devices/ios/ios.js

@@ -825,7 +825,7 @@ IOS.prototype.detectUdid = function (cb) {
         }
 
         if (stdout && stdout.length > 2) {
-          this.args.udid = stdout.replace("\n", "");
+          this.args.udid = stdout.split("\n")[0];
           logger.debug("Detected udid as " + this.args.udid);
           cb();
         } else {