Bug 19418: (bug 12833 follow-up) Add missing use statement

Bug 19418: (bug 12833 follow-up) Add missing use statement

Patron search fail on calling svc/members/search. This script
return a 500 error and the search stay on "Processing..."

Test plan:
  - Enable ExtendedPatronAttributes system preference,
  - make a standard search (search fields),
  - check the search works and it doesn't stick on "Processing..."

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
I do not recreate the issue, but the change make sense and the issue has
been raised by several people