[1.7.x] Fixed #23132 -- Removed confusing clause in auth docs.

Backport of abb97cffdf from master
[1.7.x] Forwardported 1.6.6 release note for #19107.

Backport of 7fcfefbc4a from master
[1.7.x] Fixed #23107 -- Made runserver output respect --no-color.

Backport of 67d7da5fb9 from master
[1.7.x] Fixed flake8 errors.

Backport of 34c60c42b6 from master
[1.7.x] Fixed #23134 -- Fixed typos in docs/ref/models/querysets.txt.

Thanks Josh Kupershmidt.

Backport of 66630f589c from master
[1.7.x] Fixed test failure on Windows.

os.close(fd) is needed to avoid "The process cannot access the file
because it is being used by another process"

Backport of c2ab501bab from master
[1.7.x] Fixed #23112 -- Field.get_choices tries to index an iterable

Backport of 97a38de230371c0b6ad8a86abba8425186c147c7 from master.
[1.7.x] Fixed the previous commit for Python3.

Backport of 4453c80634fb72b60e849480e52c06b570c696d5 from master.