Bug 17653: Remove itemtype-related t/db_dependent/Circulation* warnings

Bug 17653: Remove itemtype-related t/db_dependent/Circulation* warnings

This patch makes t/db_dependent/Circulation* create
good sample data for its tests. It does so by creating a random
itemtype.

To test:
- Run
  $ prove t/db_dependent/Circulation*
=> FAIL: lots of warnings about "item-level_itypes set but no itemtype
set for item"
- Apply the patch
- Run:
  $ prove t/db_dependent/Circulation*
=> SUCCESS: Tests are green, and no warnings.
- Sign off :-D

Sponsored-by: ByWater Solutions
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Katrin Fischer  <katrin.fischer@bsz-bw.de>
Signed-off-by: Mason James <mtj@kohaaloha.com>