Bug 23271: (QA follow-up) Make search_with_library_limits fallback to userenv if...

Bug 23271: (QA follow-up) Make search_with_library_limits fallback to userenv if required

This patch makes  the generic method rely on C4::Context->userenv if the
library_id is not passed.

To test:
1. Apply this patch
2. Run:
   $ kshell
  k$ prove t/db_dependent/Koha/Patron/Attribute/Types.t
=> SUCCESS: Tests pass!
3. 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: Jonathan Druart <jonathan.druart@bugs.koha-community.org>