Bug 17572: Remove itemtype-related warnings from issue.t

Bug 17572: Remove itemtype-related warnings from issue.t

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

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

Sponsored-by: ByWater Solutions
Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Mason James <mtj@kohaaloha.com>