Refactored cache expiry logic for Locmemcache to make consistent across
all places where accessed, and correctly handle None as expiry time.

Compare parameters instead of re.pattern instances, and add the other
parameters to the comparison. Also add a __ne__ to make assertNotEqual
work properly.

Oracle and SQL Server don't have exactly the same limitations. It's
worth treating them differently.

This reduces the number of explicit vendor checks.

It's the one shown when the optional integration described in
https://docs.djangoproject.com/en/dev/ref/contrib/admin/#adding-a-password-reset-feature
is used.

Follow-up to commits 6f470650 and 1d42a86e, together they fix
different small UI regressions after a962286b.

Refs #21293.

Insert space

You're not allowed to do this after you've made migrations; see ticket
for more details.

Thanks david.fischer.ch at gmail.com for the report.

Refs #20610.

In some cases, this could lead to migrations written with Python 2
being incompatible with Python 3.
Thanks Tim Graham for the report and Loïc Bistuer for the advices.

Refs #22564.

This change is required after the introduction of
SessionAuthenticationMiddleware to the default middleware

Thanks Anubhav Joshi and Tim Graham for the reviews.

Ordering by reverse foreign key was broken by custom lookups patch
(commit 20bab2cf).

Thanks to everybody who helped solving this issue. Special thanks to
Trac alias takis for reporting this.

When custom lookups were added, converting the search lookup to use
the new Lookup infrastructure wasn't done.

Some changes were needed to the added test, main change done by
committer was ensuring the test works on MySQL versions prior to 5.6.

Thanks adminq80 at gmail.com.

Thanks Florian Apolloner for noticing the issue and Aymeric
Augustin for the expertise.
Refs #22540.