In relation to #25293, it solves the improbable case where the OS returns the
mount options as names instead of numeric ids. The module converts these names
to numeric ids before returning the opts.
This is done only for uid= and gid= opts, for now. It can be extended to others.
I currently don't have access to an OpenBSD system, so I don't know what
the 6 columns of output of `swapctl -kl` is since some of the outputted
columns are discarded by the mount module, but as they are discarded,
they do not affect the tests of mount.swaps.
