[1.6.x] Fixed #21869 -- Fixed docs building with Sphinx 1.2.1.
[1.6.x] Fixed #21869 -- Fixed docs building with Sphinx 1.2.1.

Thanks tragiclifestories for the report.

Backport of e1d18b9d2e from master

redhat-openstack/django,django-nonrel/django,redhat-openstack/django,django-nonrel/django,redhat-openstack/django,redhat-openstack/django,felixjimenez/django,dex4er/django,dex4er/django,felixjimenez/django,django-nonrel/django,felixjimenez/django,felixjimenez/django,dex4er/django,django-nonrel/django