The 'announce timer' will be used by migration, and explicit
requests for qemu to perform network announces.
Based on the work by Germano Veit Michel <germano@redhat.com>
and Vlad Yasevich <vyasevic@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
