Bug 14464: Add ability to cancel waiting holds from checkin screen

Bug 14464: Add ability to cancel waiting holds from checkin screen

Test plan:

    1. Ensure that ExpireReservesMaxPickUpDelayCharge is set to 0.
    2. Place a hold (doesn't matter whether it's a bib/item-level hold),
       then confirm the hold by checking it in.
    3. Check in the item again, and hit Cancel.
    4. The reserve in question should be cancelled.
    5. Repeat steps 2-4 twice, once after setting
       ExpireReservesMaxPickUpDelayCharge to a nonzero value and again
       after clicking the "Forgive fees for manually expired holds"
       checkbox.

A fine should only be applied when the syspref is enabled and the
checkbox is not checked. Also, the checkbox should only appear after
enabling the syspref. And finally, the checkbox should remember whether
it is checked across multiple checkins, same as the "Forgive overdue
charges" and "Book drop mode" checkboxes.

Signed-off-by: Jason Burds <jburds@dubuque.lib.ia.us>

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Amended patch: Removed 2 debugging lines.
Signed-off-by: Tomas Cohen Arazi <tomascohen@unc.edu.ar>