Bug 16501: Remove some unneeded warns in Upload.t

Bug 16501: Remove some unneeded warns in Upload.t

At some point I saw some gain in warning about a missing config line.
But these warns are actually not needed here.
Removing them here.

Test plan:
Run t/db_dependent/Upload.t while having upload_path in your koha-conf and
also without it.

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
(cherry picked from commit e8117033e4c41247f453a9fb2488dc9568ab642f)
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>