[1.0.X] Fixed #9645 -- Work around a backwards-incompatibility in Sphinx so that

various combinations of released docutils and sphinx versions all work
together. Thanks, Ramiro Morales.

Backport of r9586 from trunk.


git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.0.X@9587 bcc190cf-cafb-0310-a4f2-bffc1f526a37