xfstests: remove stale machine configs

xfstests: remove stale machine configs

Left over from the days of ASG, all stale. Remove them, leaving just
an simple example that defines all the variables that can be
configured. Also, add a localhost defined config set up for simple
KVM based guest test configs using virtio for their block devices to
simplify test setup in such scenarios..

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Phil White <pwhite@sgi.com>
Signed-off-by: Rich Johnston <rjohnston@sgi.com>