Needed for tests for migrations handling of database defaults.

This method is unused since 8717b066.

This reverts commit da79ccca.

This optimized the unsuccessful case at the expense of the successful one.

Thanks Anssi Kääriäinen, Marc Tamlyn, and Tim Graham for the reviews.

An explicit `__exact` lookup in the related managers filters
was interpreted as a reference to a foreign `exact` field.

Thanks to Trac alias zhiyajun11 for the report, Josh for the investigation,
Loïc for the test name and Tim for the review.

Reference: http://lh.2xlibre.net/locale/fa_IR/

Django imports threading in many other places without fallback.

Removed unused method and updated docstrings.

Thanks Tom Christie for the report and review.

and deprecated django.forms.extras.

Thanks Berker Peksag and Tim Graham for the reviews.

Thanks Berker Peksag and Tim Graham for the reviews. Refs #24219.

Thanks Collin Anderson and Tim Graham for the reviews.

Forwardport of 3d4a8261 from stable/1.7.x

Python change is http://bugs.python.org/issue22032