This enables us to remove custom Atffiles whose only purpose was to avoid
using the helpers as tests.
XXX src/tests/dev/dm/ is not (yet) linked into the build!
- The use.fs property is gone.
- Mark the tests/fs/t_create:attrs test as broken when using the default
unprivileged-user:_atf setting. This probably deserves a fix somehow
but I'm not sure at this point.
and dm_targets_list ioctl to test if dm driver inside rump works.
It will be disable for now, because I need to find out why if I run this
test by atf-run it fails while running h_dm by hand works.
XXX. component.c in rump/libdm calls devsw_attach before dm_modcmd can do
that therefore unmodified modcmd returns error.
