mount: add support for OpenBSD

Add support for missing functions that make sense on OpenBSD.
Use strip() instead of replace().
Merge branch 'obsd-mount' of https://github.com/ajacoutot/salt into ajacoutot-obsd-mount
Fix lint for #15419
Merge pull request #15431 from thatch45/ajacoutot-obsd-mount

merge #15419