Partial revert of 81768fc7 (#6398) (#6430)
Partial revert of 81768fc7 (#6398) (#6430)

This queryset introduced a bug where a from_url of 5 characters would
produce and exception.
rtfd/readthedocs.org,rtfd/readthedocs.org,rtfd/readthedocs.org,rtfd/readthedocs.org