This reverts commit 49eee842 as it caused
a regression with test mirrors.

mysqlclient 1.3.7 fixes the test failures caused by 1.3.6.

A @font-face declaration may contain a fragment that looks like a relative path,
e.g. @font-face { src: url('../fonts/font.svg#../path/like/fragment'); }
In this case, an incorrect path was passed to the storage backend, which raised
an error that caused collectstatic to crash.

Thanks Aymeric for the initial patch and Carl for review.

Bail early if the input is a string since that's the most common case.

Thanks Josh, Anssi, and Carl for reviews and advice.

Forwardport of 3ded51bc from stable/1.8.x

Thanks to Kevin Turner for the report and Tim for the review.

Removed the bit about not allowing assignment to variables
because simple_tag now allows this.

This is consistent with the behavior of Django 1.7.x and earlier.

Thanks to Jamie Matthews for finding and explaining the bug.

Forwardport of 8c8a6d8a from stable/1.8.x

psycopg2 now publishes binary wheel files for Windows
so you can install it using pip.

Thanks Jacek Bzdak for indepdently contributing a similar fix.

This fixes a regression from refs #25496.