cgroups: add check for lxc.cgroup.use
cgroups: add check for lxc.cgroup.use

Closes #870.

Signed-off-by: Marcos Paulo de Souza <0b4ebe3a213a49a2bc3457b98408e6d86812eb46@gmail.com>

caglar10ur/lxc,thmo/lxc,hallyn/lxc,ss1h2a3tw/lxc,hallyn/lxc,caglar10ur/lxc,ss1h2a3tw/lxc,thmo/lxc,ss1h2a3tw/lxc,hallyn/lxc,caglar10ur/lxc,thmo/lxc