Bug 29860: Remove item type-related warnings

Bug 29860: Remove item type-related warnings

To test:
1. Run:
   $ kshell
  k$ prove t/db_dependent/selenium/regressions.t
=> FAIL: You see several
item-level_itypes set but no itemtype set for item (985) at /kohadevbox/koha/Koha/Schema/Result/Item.pm line 905.
2. Apply this patch
3. Repeat 1
=> SUCCESS: No more item type warnings
4. Sign off :-D

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>