- can't use *bogus* as a key unless that's allowed by
the schema -- and it is not.
- can't supply empty config if there is supposed to be
an object there.
This makes it a little difficult to allow a config-file
that is actually no-configuration-at-all (or only-defaults).
Put in values for *btrfsSwapSubvol* since it isn't a fragile
setting.
cdbc7fffca