Bug 25617: (bug 25133 follow-up) 12 PM is not 24 but 0

Bug 25617: (bug 25133 follow-up) 12 PM is not 24 but 0

There was an error in the precedent code, in 12hr format, 12PM is
actually 00:00

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>
Signed-off-by: Alex Arnaud <alex.arnaud@biblibre.com>

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
(cherry picked from commit dd0c7c55fc2b5f0a312055d0c051b166d75ea82d)

Signed-off-by: Aleisha Amohia <aleishaamohia@hotmail.com>