systemd services restarting indefinitely on initial install

If you install the packages without configuring the associated database, then you have debusine-server.service and debusine-server-celery.service that fail to start and that keep being retried in loop (I noticed because my laptop fan was running while it was supposed to be idle...).

debusine-server.service fails at "/usr/bin/debusine-admin check" (PreExecStart).