js error: Pace.js pulgin conflict for the "xhr.open()" method

[gaojianzhuang]

If the page reference the "Pace.js" plugin, because the pace JS override the "xhr.open" method, the third parameter is not default true, this will cause the "xhr.open" in the cropper throw an exception, I think we should change the code to “xhr.open('get', url, true);” instead of the “xhr.open('get', url);”. This change will avoid the js error.

FYI.

[fengyuanchen]

The third parameter is optional and default to true according to spec: https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/open