[1.5.x] Fixed #19776 -- Added missing import for backport

line was present on master from 1520748dac95a7f114e4bb2feeee04d46c720494
[1.5.x] Fixed #19779 -- Checked contrib.sites presence in RedirectFallbackMiddleware

Thanks Aymeric Augustin for the report and directions for the patch.
Backport of 2ed90eac from master.
[1.5.x] Cleaned up some lingering signals in the test suite that were causing spurious failures with Pypy and Postgres.
Backport of db09a2de6e1bc7121
[1.5.x] Fixed #19749 -- Documented ending param to command's self.stdout/err

Thanks xian at mintchaos.com for the report.
Backport of 0201b9d6d from master
[1.5.x] Fixed #19699 - Removed "Please see the release notes" from versionadded/changed directives

Thanks Aymeric for the patch.

Backport of d93edffa89 from master.
[1.5.x] Made modwsgi groups_for_user consistent with check_password

2b5f848207b1dab35afd6f63d0107629c76d4d9a based its changes on #19061
that made the is_active attribute mandatory for user models.
The try/except was not removed for the groups_for_user function.

refs #19780
[1.5.x] Fixed #19645 -- Added tests for TransactionMiddleware

Backpatch of f556df90be995a83b979cf875705d98521ab4dc7. Backpatching
these tests so that it will be easier to backpatch the fix for #19707.
[1.5.x] Fixed #19707 -- Reset transaction state after requests

Backpatch of a4e97cf315142e61bb4bc3ed8259b95d8586d09c
[1.5.x] Fixed #19638 -- Skipped tx support testing for some DBs

PostgreSQL and Oracle always support transactions, so the create table
and rollback test is non-necessary on those DBs.

Thanks to shai for report.

Backpatch of 0478780b8efdfcbc0d2c17f1459cac45701e1d86
[1.5.x] Fixed #19720 -- Oracle ordering related delete regression

When a query had a complex where condition (a condition targeting more
than the base table) a subquery was used for deletion. However, the
query had default ordering from the model's meta and Oracle doesn't
work with ordered subqueries.

The regression was caused by fast-path deletion code introduced in
1cd6e04cd4f768bcd4385b75de433d497d938f82 for fixing #18676.

Thanks to Dylan Klomparens for the report.

Backpatch of 8ef3235034a1a7616714a5d61486dc68536f74ee
[1.5.x] Fixed #19112 -- Reduced the amount of query params in a test

Backpatch of 604d8763dc2c901a3557e15880895d88af5c4127.
[1.5.x] Emphasized MyISAM pseudo-requirement for GeoDjango over MySQL

Refs #15295.
Backport of 8fbc20b24 from master.
[1.5.x] Made custom m2m fields without through easier to use

The change in f105fbe52b21da206bfbaedf0e92326667d7b2d4 made through=None
m2m fields fail in cases where they worked before. It isn't possible to
create such fields using public APIs. The fix is trivial, so it seems
worth adding it.

This is not a backport from master. Master has gotten enough other
changes to related fields internal API that this fix alone isn't enough
to do any good.
[1.5.x] Removed try-except in django.db.close_connection()

The reason was that the except clause needed to remove a connection
from the django.db.connections dict, but other parts of Django do not
expect this to happen. In addition the except clause was silently
swallowing the exception messages.

Refs #19707, special thanks to Carl Meyer for pointing out that this
approach should be taken.
[1.5.x] Fix admindocs on Python 3, where None cannot be sorted with strings.

This fixes two tests in admin_views which were failing on Python 3, but only if
the tests were run with docutils installed.
[1.5.x] Fixed #19823 -- Fixed memcached code example in cache docs

Backport of 668d0b8d from master.
[1.5.x] Fixed #19729 -- Removed leftover refactoring helper variables.

Thanks chrismedrela for the report.

Refs #6262, 44b9076 and 4d94c0c.

826d9de00e74a53d7cc65fcb2aaa5ccdf33674ab from master.
[1.5.x] Typo in i18n docs.

112c6e987dbe789c8eb1889852f6056131c8d4d6 from master.
[1.5.x] Mention backward relationships in aggregate docs.

Thanks Anssi and Marc Tamlyn for reviewing.

Fixes #19803.

0560bfb705687c831e2769b1202706e2ceb1f7a7 from master.
[1.5.x] Fix filtering during collection of paths in setup.py

Thanks Marek Brzóska for the report.

f179a5198e05e1be8ba8be87c1f0e1a8924cf005 from master.