Now `systemctl --user stop docker` completes just with in 1 or 2 seconds.
Fix issue 41944 ("Docker rootless does not exit properly if containers are running")
See systemd.kill(5) https://www.freedesktop.org/software/systemd/man/systemd.kill.html
Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
(cherry picked from commit 05566adf716e85cdd5b512bc5fad4689e78c56fc)
Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>