accomodate systemd's init.scope cgroup
accomodate systemd's init.scope cgroup

systemd 226 places itself into /init.scope.  Allow it to escape
that.  Note this means there are two cgroup names one should not
use to try to confine applications - init.scope and
/system.slice/cgproxy.service.  However those shouldn't be
commonly used.

Signed-off-by: Serge Hallyn <3df611b026e4639bee8aef7a4beb2e39fcebb313@ubuntu.com>

lxc/cgmanager,hallyn/cgmanager,hallyn/cgmanager,lxc/cgmanager