Provide better pointers to mysql_tzinfo_to_sql for MySQL users

[Aymeric Augustin]

The exception "ValueError: Database returned an invalid value in QuerySet.dates(). Are time zone definitions and pytz installed?" is quite hard to diagnose when users omitted to run mysql_tzinfo_to_sql.

Technically it says the right thing (time zone definitions aren't installed) but it's hard to locate the information, as it isn't in the MySQL installation docs nor in the time zone docs. I just spent a few minutes searching it in the docs, and I wrote these docs!

I suggest adding it to the time zone FAQ and to the MySQL installation instructions (at least).

[anonymous]

I've changed USE_TZ = TRUE by USE_TZ = False for solved this problem

[loic84]

FWIW I've slightly improved this error message on master: [32e75803].

[Aymeric Augustin]

The anonymous has done exactly what this errors message is designed to prevent.

Documentation improvements are absolutely needed.

[loic84]

I agree that docs are needed, with a link to the relevant mysql docs. Do the other db require a similar treatment? I fixed the error message a while ago after hitting the problem with the test suite. Maybe the error message commit should be backported to stable as well?

MySQL docs: ​http://dev.mysql.com/doc/refman/5.5/en/mysql-tzinfo-to-sql.html

[Tim Graham]

I backported the error message improvement and here's a draft patch.

[Simon Charette]

lgtm

[Tim Graham <timograham@…>]

In d8d83777ebbe15af7587a24698435555ba3bb842:

Fixed #21629 -- Added instructions for loading MySQL time zone definitions.

Thanks Aymeric for the suggestion.

[Tim Graham <timograham@…>]

In 62f282a265ae7f8d051f7ce79788cfc1a84d1a24:

[1.6.x] Fixed #21629 -- Added instructions for loading MySQL time zone definitions.

Thanks Aymeric for the suggestion.

Backport of d8d83777eb from master