Bug 7703: Don't block bulk hold action on search results if some items can't be place...

Bug 7703: Don't block bulk hold action on search results if some items can't be placed on hold

If you select multiple titles on the search results page in order to
place a bulk hold and some of those titles have no items you get a
JavaScript alert warning you can some cannot be placed on hold. You are
blocked from completing the action until you deselect the invalid hold.

This is unnecessary because the bulk hold process will safely refuse to
place a hold on these titles later in the process.

This patch removes the check that prevents submitting a multi-hold if
one or more records in the multi-hold have no items.

Test plan:
1) Apply patch
2) On the staff interface, do a search
3) On the search results, select at least one record with items and one
   record with no items.
4) Click the 'Place hold' button.
5) You should be redirected to reserve/request.pl with the message
   "Cannot place hold: this record has no items attached."

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Sally <sally.healey@cheshiresharedservices.gov.uk>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>