Bug 26268: (QA follow-up) Split DB update checks

Bug 26268: (QA follow-up) Split DB update checks

This patch splits the DB update such that the 'paidfor' field is checked
for distinctly in the deleteditems table rather than assuming if it
exists in the items table it will also exist in deleteditems.

We also correct the check as highlights by Julian.

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>