Bug 18976: (follow-up) Fix t/db_dependent/Search/History.t cleanup

Bug 18976: (follow-up) Fix t/db_dependent/Search/History.t cleanup

Same problem in t/db_dependent/Search/History.t.

To replicate:
1. Check the row count of borrowers, branches, categories, sessions, sms_providers
   tables
2. prove t/db_dependent/Search/History.t
3. Repeat step 1
4. Observe borrowers the following tables have increased in row count:
   - borrowers
   - branches
   - categories
   - sessions
   - sms_providers

To test:
1. Before applying the patch, go through steps at "To replicate" plan
2. Apply patch
3. Go through steps at "To replicate" plan
4. Observe step 4 no longer applies and those tables have the same number of
   rows as before executing the test.

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