Bug 17917: [QA Follow-up] Reprove Search.t

Bug 17917: [QA Follow-up] Reprove Search.t

The config tweaks from Search.t break check_sysprefs.t later on.
Clearing the cache resolves that.

Test plan:
[1] Run prove t/db_dependent/Search.t t/db_dependent/check_sysprefs.t (in
    one statement) before and after applying this patch.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
A prove t/db_dependent did not fail check_sysprefs.t (only skipping two
tests: 00-strict.t and Koha/IssuingRules.t; not enough patience)

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>