We don't honour the QEMU default machine type anymore, always using the
libvirt chosen default instead. The QEMU argv parser, however, will need
to know the exacty QEMU default, so we must record that info.
Reviewed-by: NJohn Ferlan <jferlan@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>