This is a followup to #4699 that addresses an oversight that could cause the CRI to relabel the host /dev/shm, which should be a no-op in most cases. Additionally, fixes unit tests to make correct assertions for /dev/shm relabeling. Discovered while applying the changes for #4699 to containerd/cri 1.4: https://github.com/containerd/cri/pull/1605 Signed-off-by: Jacob Blain Christen <jacob@rancher.com>