Tender widget inavailability stops loading studio page

When tender_widget.js is inavailable studio page stops
loading becuase of error in the requirejs. It is
dependency in the requirejs so when it doesn't load
it cause other dependencies to stop loading.

TNL-1018
for tests change the default xml data dir to a place where it will get cleaned up
Merge pull request #6306 from edx/hotfix/2014-12-18

Tender widget inavailability stops loading studio page