Bug 13104 - Changing date or time format on a production server will create duplicate...

Bug 13104 - Changing date or time format on a production server will create duplicate fines!

The system preference TimeFormat decides if times are formatted in 24
hour or 12 hour format. The issue at hand is that this changes the time
description for fines. Let us assume the time format is currently 24
hour, and there are overdue items with accruing fines. When the format
is changed to 12 hour, and fines.pl is run, it will begin looking for
fines with a 12 hour format. Since there are no, it will create a new
fine and you will now have two fines for the same item!

There are solutions which require database manipulation:
1) Update all existing fines from 24 hour to 12 hour format
2) Delete all existing accruing fines so they are all regenerated the
following night

The same situation applies to DateFormat.

The accounts rewrite ( Bug 6427 ) will resolve this issue, as it does
not look for existing fines based on the description.

I believe the best course of action until bug 6427 is pushed to master
is to add a warning to the system preference to not alter it on a
production server with existing fines.

Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Adds some documentation to warn about the problem.
Tested the new addition shows up in po files.

Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>