jenkins-build-all just sets `build_server_always = True`, these tests need
a whole keystore setup. So just delete the existing config, and let
`fdroid init` do the rest.
The setup and build_all jobs take a very long time to run, so its really
annoying when they are marked as failed just because one small thing in the
test suite failed. So move the test suite to its own job that can be run
more frequently.