Fixed #7831: be case-insensitive when in `get_language_from_request`.
Fixed #7831: be case-insensitive when in `get_language_from_request`.

--HG--
extra : convert_revision : svn%3Abcc190cf-cafb-0310-a4f2-bffc1f526a37/django/trunk%408561

adieu/django-nonrel,adieu/django-nonrel,adieu/django-nonrel