Bug 13459: Fix datatables paging for patron lists

Bug 13459: Fix datatables paging for patron lists

The display of the datatables paging options for the
patron list feature is broken.

To test:
- Go to tools > patron lists
- The paging for the 'list of lists' is broken
- Select a patron list 'Add more patrons'
- Notice the paging on this page is also broken
- Apply patch
- Verify both pages now display the paging correctly

Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>
Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>