Exclude copies that have been deleted from showing up on the browse holds shelf list.

If an item had been deleted while it had a status of On Holds Shelf, it would permanently show up on
the browse holds list. This will exclude deleted copies from the results.

Signed-off-by: Steven Callender <stevecallender@esilibrary.com>
Signed-off-by: Mike Rylander <mrylander@gmail.com>