Oauth URL malformated

[unicode-it]

The URL cannot be parsed by the auth provider, because it contains a wrong '&' character at the beginning of the query params.

http://localhost:8000/o/authorize/?&client_id=client_id&redirect_uri=...

The bug is in function oauth2:

  for (key in data.params) {
    params += '&' + key + '=' + encodeURIComponent(data.params[key]);
  }

[unicode-it]

Could maybe fix like this:

  let paramsArr = [];
  Object.keys(data.params).forEach((key) => {
    paramsArr.push(key + '=' + encodeURIComponent(data.params[key]));
  } );
  params = paramsArr.join('&');

[websanova]

alright, this is in 4.1.7, thx!.