Partial backport of afe0bb7b from master.

Backport of c68ce187 from master

There is no BCryptSHA512PasswordHasher.

Backport of 8048411c from master

Backport of ea754289 from master

[1.8.x] Fixed #26034 -- Fixed incorrect index handling on PostgreSQL on Char/TextField with unique=True and db_index=True.

Thanks Simon Charette for review.

Backport of 56aaae58 from master

Backport of 54d3ba84 from master

Backport of db8f4624 from master

Backport of 44930cc4 from master

Thanks Jens Lundstrom for the report and Tim Graham for the review.
Backport of 632a9f21 from master.

Backport of 7cc2efc2 from master

Backport of 1e57dccb from master

Refs 1014ba02

Backport of 2765adc8 from master

Backport of 24c1713e from master

Backport of 3eba9638 from master

Django's test suite often tries to load fixture files from apps that have
no fixtures at all. This creates a lot of unnecessary disabling and
enabling of constraints which can be expensive on some database.

To speed this up, loaddata now first checks if any fixture file matches.
If no fixture file is matched, then the command exits before disabling
and enabling of constraints is done.

The main benefit of this change is seen on MSSQL, where tests on
Django 1.8 run hours faster.

Backport of ee9f4686 from master

Backport of 7df9aa3a from master

Backport of 69208a5a from master

Backport of 300de968 from master

This test sometimes fail because the checked integers can appear in the
output as memory addresses due to #24316.

Backport of 2939ed4a from stable/1.9.x

Backport of 4a438e40 from master

The use of predictable filenames in /tmp often leads to symlink attacks
so remove the most obvious use of them in the docs.

Backport of 77b8d8cb from master

Backport of 91cd4d8e from master

Backport of 32c7d93e from master

Backport of 5081adcb from master

Backport of 36d0aa43 from stable/1.9.x

This fixes a regression introduced by a5f6cbce.
Thanks Gavin Wahl for the report and Tim Graham for the review.
Backport of cd3c042b from master.

Backport of e0900707 from master

Thanks to Geoffrey Sechter and the Django NYC group for the report and Markus
for the review.

Backport of c4e372aa from master

Backport of ffcdb0b4 from master

Backport of a44dc200 from master

Thanks to Emanuele Palazzetti for the help.

Backport of 3a36c807 from master

The test creates and deletes a model in the same migration, and the model
had an AutoField. On Oracle, AutoField's are set up using deferred SQL, which
in this case was trying to modify a table after it had dbeen removed.

Backport of c8b3fbe2 from master

Referencing URLs by dotted path is a stronger convention than
importing the URLs.

Backport of 179fbab7 from master

Backport of 542b7f6c from master

Backport of 1aa8bf9b from master

Backport of ec708803 from master

Thanks Justin Abrahms for the report.

Backport of 166e0490 from master