LP1910546 Prevent Copy Location Delete With Active Copies

LP1910546 Prevent Copy Location Delete With Active Copies

Raise a database exception when any attempt is made to marke a copy
location as deleted when the location contains non-deleted copies.

To Test:

1. Navigate to /eg2/staff/admin/local/asset/copy_location

2. Attempt to delete a copy location that is known to contain
   non-deleted copies.

3. Confirm an error message is displayed and the location is not marked
   as deleted.

Signed-off-by: Bill Erickson <berickxx@gmail.com>
Signed-off-by: Tiffany Little <tlittle@georgialibraries.org>
Signed-off-by: Michele Morgan <mmorgan@noblenet.org>