This will cause systemd to delete the lock file when the service
terminates. This does not do anything if lorax-composer is started on
the command line, however.
Normally tmpfiles.d will handle this at boot time, but if you install
lorax-composer without rebooting it was ending up with root:root
ownership instead of root:weldr
Also make sure the recipe directory and its contents have correct
ownership, and change the default recipe path when using the systemd
service to /var/lib/lorax/composer/recipes/