Bug 32247: Exit holds queue builder if there are no holds on the biblio
update_queue_for_biblio currently
1 - gets the holds on a bib
2 - gets the items available to fill any holds
3 - combines these to build the queue, exiting if there are no holds or items
If there are no holds at step 1, we don't need to do step 2 or 3
This patch simply deletes the queue for this biblio, then exits if there are no holds