Bug 11182: (QA followup) fix warning if itemBarcodeFallbackSearch set

Bug 11182: (QA followup) fix warning if itemBarcodeFallbackSearch set

To reproduce:
- On top of the previous patches, if you enable the
  itemBarcodeFallbackSearch syspref and do a search for a term that
  returns at least one result, there will be warnings for each result
  without items attached.

To test:

- In the checkout form enter a term that should return results (some of
  them without items attached)
=> There are warnings on the logs regarding a split of undef variable
- Apply the patch
- Repeat the first step
=> No warnings

Signed-off-by: Galen Charlton <gmc@esilibrary.com>