tests: allow to run API tests on live db

This simplify the database test handling, and allows us to run the API tests
against a real database, revealing brand new bugs!

Change-Id: I39d8c1db5706dcba101799871b89d31e8d51d400
Signed-off-by: Julien Danjou <julien@danjou.info>
Merge "tests: allow to run API tests on live db"