Share /var/lib/kubernetes on startup

Kubelet makes sure that /var/lib/kubelet is rshared when it starts.
If not, it bind-mounts it with rshared propagation to containers
that mount volumes to /var/lib/kubelet can benefit from mount propagation.

pkg/util/mount/mount_unsupported.go

@@ -67,6 +67,10 @@ func (mounter *Mounter) PathIsDevice(pathname string) (bool, error) {
 	return true, nil
 }
 
+func (mounter *Mounter) MakeRShared(path string) error {
+	return nil
+}
+
 func (mounter *SafeFormatAndMount) formatAndMount(source string, target string, fstype string, options []string) error {
 	return nil
 }