rng-tools: fix very long shutdown delay with systemd
The systemd service file has DefaultDependencies=no but is not
properly configured to also stop the unit. Because of this the unit
keep running after shutdown but systemd still waits for it to finish to
then later resort to a hard kill. All this take 1m30s with the default
configuration.
To fix this problem add the missing Before=shutdown.target and
Conflicts=shutdown.target to have systemd stop the unit on shutdown.
Signed-off-by: Alban Bedel <alban.bedel@aerq.com> Signed-off-by: Armin Kuster <akuster808@gmail.com>
