Some completers for libvirt related tools might want to list
domain IDs only. Just like the one I've implemented for
virt-viewer [1]. I've worked around it using some awk magic,
but if it was possible to just 'virsh list --id' then I could
drop awk.
1: https://www.redhat.com/archives/virt-tools-list/2019-May/msg00014.html
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Martin Kletzander <mkletzan@redhat.com>