[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.

option_group_changed('port', 'main', 'web')
option_group_changed('query-log-file', 'main', 'web')
option_group_changed('profile', 'main', 'web')
option_group_changed('max-post-length', 'main', 'web')