Bug 15357: Display existing holds even if no items exist

 Bug 15357: Display existing holds even if no items exist

If all the items have been deleted for a record and holds exist, the
holds are not displayed.
You are not able to delete the items from the record detail page, but
you can from the items page.

Test plan:
1 - Place 1 or more title level holds on a record.
2 - Delete each item individually.
3 - Note that you see the number of holds on the record details page
With this patch, that holds are accessible via the holds tab.

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Brendan A Gallagher <brendan@bywatersolutions.com>
(cherry picked from commit 0e4b703d239551207ca72c5b201475418c7cfd9c)
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>