[qunit] remove unused 'data_files' parameter Its use was removed when we stoppped pointing firefox at file:// web/test/jstests/ajax_url2.html has never actually been used, it's only been ever mentioned in a QUnit comment.

     1

missing-dep-for-interpreter make => make | build-essential | dpkg-dev (usr/*/cubicweb/skeleton/debian/rules.tmpl)