Bug 38148: Check value of holdallowed circ rule properly

Bug 38148: Check value of holdallowed circ rule properly

It was noted on Bug 29087 that the value of circulation rules needs to be checked differently, so this follow-up addresses that.

To test:

1. Apply patch and restart services
2. Search for a record on the OPAC. Confirm you can see a link to place a hold.
3. Search for this record on the staff interface and place a hold. Go to Circulation -> Holds to pull and confirm your hold shows in the list.
4. Confirm tests still pass t/db_dependent/Koha/Holds.t

Sponsored-by: Whanganui District Council
Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: andrewa <andrew.auld@ptfs-europe.com>
Signed-off-by: Ray Delahunty <r.delahunty@arts.ac.uk>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>