Bug 24705: Holds placed via SIP will be given first priority

Bug 24705: Holds placed via SIP will be given first priority

The SIP server does not calculate and pass a priority to AddReserve, which causes the hold to be given priority 1.

Test Plan:
1) Place a hold via SIP for a record with existing holds
2) Note the new hold is top priority
3) Apply this patch
4) Restart SIP
5) Repeat step 1
6) New hold should be last priority

Signed-off-by: Christofer Zorn <Christofer.Zorn@ajaxlibrary.ca>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>