Bug 14866: Make high holds work with different item types

Bug 14866: Make high holds work with different item types

To test:
1) Apply patch, update database, restart services
2) Enable decreaseLoanHighHolds sysprefs if not already active
3) Go to circulation rules and set a value under 'Decrease loan holds
(day)' that is DIFFERENT from decreaseLoanHighHoldsDuration
4) Check out an item with holds and confirm that the value from the rule
is used instead of the system preference
5) Confirm tests pass before and after the patch
t/db_dependent/DecreaseLoanHighHolds.t

Sponsored-by: Catalyst IT
Signed-off-by: Lisette Scheer <lisetteslatah@gmail.com>
Signed-off-by: Henry Bolshaw <bolshawh@parliament.uk>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>