Bug 21105: (QA follow-up) Silence warning because of tests setup

Bug 21105: (QA follow-up) Silence warning because of tests setup

The tests are using 'http://localhost' and the regex is setting $baseURL
to empty in this case. It works on the oai.pl front-end.

This patch changes the regex.

To test:
1. Run:
   $ kshell
  k$ t/db_dependent/OAI/Server.t
=> FAIL: Boo! Warning!
2. Apply this patch
3. Repeat 2
=> SUCCESS: Oh, cool. No warning :-D
4. Sign off :-D

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>