Bug 20008: Fix restrictions added from memberentry.pl if TimeFormat is 12hr

Bug 20008: Fix restrictions added from memberentry.pl if TimeFormat is 12hr

Test Plan:
1) Set TimeFormat to 12 hour
2) Add a restriction with an expiration date via memberentry.pl
3) Note the restriction exists, but has no expiration date
4) Apply this patch
5) Repeat step 2
6) Note the restriction exists and has an expiration date!

Signed-off-by: Roch D'Amour <roch.damour@inlibro.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>