the cgroups experimental feature does not work properly without this
because we do not stop subdaemons when the main daemon is shut down.
systemd needs the assigned cgroups to be empty to restart the daemon
and thus cannot cleanly restart the daemon if any connections exist.
starting a fresh unit for each connection creates a new cgroup every
time instead of sharing any delegations and thus solves the problem.
fixes#1030
Change-Id: Id6c458aad30eaa08c3609ac8280a7dde8e8f3cf9