fix cg_access() for controller directories
fix cg_access() for controller directories

The previous patch actually didn't handle those, but only
/cgroup itself.

Closes #107

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

Xeno22/lxcfs,Xeno22/lxcfs