Bug 16965: [Follow-up] Adjust get_object_class

Bug 16965: [Follow-up] Adjust get_object_class

In many cases it should be possible to derive the Koha::Objects class
name from the DBIx result class name in a trivial manner.
If not, the DBIx result class should have a class method called
koha_objects_class providing that non-trivial name, such as Libraries
for Branch.

Note: We are only interested in the plural form here (Koha::Objects).

Test plan:
Run t/db_dependent/Koha/Objects.t

Signed-off-by: Marc Véron <veron@veron.ch>
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>