Bug 16532: Groups showing empty tables if no groups defined

Bug 16532: Groups showing empty tables if no groups defined

EDIT: Same change for libraries

To test:
1) Go to Admin -> Libraries and Groups
2) Notice empty tables if nothing defined
3) Apply patch and refresh page
4) Empty tables should not show
5) Add a new group
6) Confirm table shows correctly

Sponsored-by: Catalyst IT
Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Brendan Gallagher <brendan@bywatersolutions.com>