Update to latest django-celery.
Update to latest django-celery.

safwanrahman/readthedocs.org,rtfd/readthedocs.org,rtfd/readthedocs.org,pombredanne/readthedocs.org,davidfischer/readthedocs.org,davidfischer/readthedocs.org,davidfischer/readthedocs.org,pombredanne/readthedocs.org,safwanrahman/readthedocs.org,rtfd/readthedocs.org,davidfischer/readthedocs.org,pombredanne/readthedocs.org,safwanrahman/readthedocs.org,safwanrahman/readthedocs.org,rtfd/readthedocs.org