cgroups: cgfsng_set: handle unified hierarchy
cgroups: cgfsng_set: handle unified hierarchy

Signed-off-by: Christian Brauner <48455ab3070520a2d174545c7239d6d0fabd9a83@ubuntu.com>

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