Bug 16561 - Bug 15877 followup to fix tests

Bug 16561 - Bug 15877 followup to fix tests

When I altered the tests to avoid accidental deletion of all items, I
didn't rollback the transaction, hence the tests now delete all items
from a db when run.

This patch rollsback the transaction so items are not deleted from your db

To test:
1 - Backup your db
2 - prove -v t/db_dependent/Barcodes.t
3 - Note that all items and issues are deleted from the DB
4 - Restore your DB
5 - Apply this patch
6 - prove -v t/db_dependent/Barcodes.t
7 - Your DB should eb unchanged

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>