Commit 2b6dd3fb4384 set the killmode of the podman.service to the
systemd default which ultimately lead to the problem that systemd
will kill *all* processes inside the unit's cgroup and hence kill
all containers whenever the service is stopped.
Fix it by setting the type to sdnotify and the killmode to process.
`podman system service` will send the necessary notify messages
when the NOTIFY_SOCKET is set and unset it right after to prevent
the backend and container runtimes from jumping in between and send
messages as well.
Fixes: #7294
Signed-off-by: Valentin Rothberg <rothberg@redhat.com>
0f4e2be073