This fixes one issue with Docker running under a grsec kernel, which
denies chmod and mknod under chroot.
Note, if pivot_root fails it will still fallback to chroot.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Upstream-commit: 85988b33d299697f410a3a92db5d537fdbee955b
Component: engine
