Bug 15288: (QA followup) Tests still point to old 500.tt file

 Bug 15288: (QA followup) Tests still point to old 500.tt file

This patch fixes the t/db_dependent/Auth.t so they don't look for the removed
file and use the new one instead.

To test:
- On master, run
  $ prove t/db_dependent/Auth.t
=> FAIL: You get something similar to this:

- Apply the patch
- Re-run the tests
=> SUCCESS: Tests now pass.

Signed-off-by: Tomas Cohen Arazi <tomascohen@unc.edu.ar>
Signed-off-by: Brendan A Gallagher <brendan@bywatersolutions.com>