This type tried to disable an unit after it has removed it, which
failed. Now the removal happens in gencode-remote, after the unit has
been stopped and disabled.
* __systemd_unit: Move systemctl detection to manifest
* __systemd_unit: Restart the unit if inactive
Until now, the --restart parameter caused the unit to be restarted
only when the unit file has changed. This commit modifies --restart
behavior so that the unit is also restarted when the unit is inactive.
* __systemd_unit: Do not create unit file when source is empty