Skip creating some mounts.

[mounts] Skip creating of cgroup mounts as systemd does them for us.

Systemd handles automatically mounting of /sys/fs/cgroup and
/sys/fs/cgroup/memory when needed.

Also exclude the auto as it is not generatig valid mount entry and
doesnt do anything anyway.

Signed-off-by: Marko Saukko <marko.saukko@jolla.com>