Bug 25133: Fix time part of due date for 12hr

Bug 25133: Fix time part of due date for 12hr

With Timeformat system preference set to 12 hours format:

Prior to 19.05.08, when due date was specified at checkout,
the time in the box would show in 24hr format (e.g. 15:59)
while the due date in the patron's checkouts would show
in 12hr format (e.g. 3:59 PM).

After 19.05.08, the format in the specify a due date box
shows in 24hr format and the due date in 12hr format
(in patron checkouts) as before.

But when checking out multiple items using the specify due
date option for the session, the time changes from PM to
AM.

To test:
- Check out an item with specified due date 15:50 PM
- Check out a second item in same transaction
- Verify date changed to AM
- Apply patch
- Repeat
- Verify this time the date is kept as set

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Kelly McElligott <kelly@bywatersolutions.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Joy Nelson <joy@bywatersolutions.com>
(cherry picked from commit 1973003eaafd4cc7f7040cc66f946751eb2bacc3)

Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>