Stop using the polyfill when you are assign the es6-promise after that anyway

es6-promise.polyfill() is broken for Chrome atm and replaces the native Promise and swallows unhandled errors.
https://github.com/jakearchibald/es6-promise/issues/70

JitsiMeetJS.js

     }
 };
 
-require("es6-promise").polyfill()
 //Setups the promise object.
 window.Promise = window.Promise || require("es6-promise").Promise;