Applied: [Xenial][0/5] cgroup namespace update

[Kamal Mostafa]

Applied to Xenial:

    Revert "UBUNTU: SAUCE: cgroup mount: ignore nsroot="
    Revert "UBUNTU: SAUCE: (noup) cgroup namespaces: add a 'nsroot='
	    mountinfo field"
    cgroup, kernfs: make mountinfo show properly scoped path for cgroup
	    namespaces
    kernfs: kernfs_sop_show_path: don't return 0 after seq_dentry call
    cgroup: fix compile warning

Thanks, Serge.

 -Kamal