virtio tc group status changes

["Michael S. Tsirkin" <mst@redhat.com>]

Hi all,

To keep the group roster up to date, I have changed the status of virtio
TC members that did not attend any past TC meetings (when we still had
them) to that of observer.

I have also sent messages to a couple of members that didn't attend
meetings since June: they have an option to become voting members or
observers.

-- 
MST