Bug 30825: Remove GetReservesControlBranch in favour of Koha::Item->holds_control_library

Bug 30825: Remove GetReservesControlBranch in favour of Koha::Item->holds_control_library

This patch removes the GetReservesControlBranch method, and replaces its
uses with the newly introduced method.

To test:
1. Apply this patch
2. Verify that placing holds from the OPAC works
=> SUCCESS: Things work as expected
3. Run:
   $ kshell
  k$ prove t/db_dependent/Reserves* \
           t/db_dependent/Hold* \
           t/db_dependent/Koha/Hold* \
           t/db_dependent/Koha/Biblio.t
=> SUCCESS: Tests pass!
4. Sign off :-D

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>