Automatic merge from submit-queue (batch tested with PRs 65548, 65598). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
Fix comments about default mount propagation
We changed Private to be default mount propagation scheme but never got around to updating
docs and comments.
/sig storage
cc @jsafrane @liggitt
```release-note
None
```
8970bb636f