Bug 19195: Preventing noisy warns when creating or editing a basket

Bug 19195: Preventing noisy warns when creating or editing a basket

To test:
1) Open the koha intranet error log
2) Go to Acquisitions -> Find or create a vendor
3) Create a new basket, filling all fields
4) Notice warns in error log
5) Edit this basket
6) Notice warns in error log
7) Apply patch
8) Create another basket, confirm warns do not show
9) Edit this basket, confirm warns do not show

Sponsored-by: Catalyst IT
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>