Bug 19712: Fix test mode for delete_records_via_leader.pl

Bug 19712: Fix test mode for delete_records_via_leader.pl

Test plan:
perl misc/cronjobs/delete_records_via_leader.pl
=> Should display a warning
perl misc/cronjobs/delete_records_via_leader.pl --test
=> Should not display a warning and script should not apply changes
perl misc/cronjobs/delete_records_via_leader.pl --confirm
=> Should not display a warning and script should apply changes

Signed-off-by: Brendan Gallagher <brendan@bywatersolutions.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>