Comment 14 for bug 1964777

Identified commit that causes this:

commit c23cbd6fa821fea8ac4ed97ca679afebe2333c8c
Author: Marc-André Lureau <email address hidden>
Date: Thu Jan 28 13:59:24 2021 +0400

    reds: start QXL devices if VM is running

    Like char devices, QXL devices need to be explicily started.

    For some historical reason, char devices are started when in running
    state. See commi bf1d9007b. Reading that commit comments, there was a
    plan to provide an API to stop/start devices invidually, but that never
    happened. Whether that API would really be useful now, I wonder.

    For now, just follow the char devices behaviour and start QXL devices
    added when vm_running.

    Signed-off-by: Marc-André Lureau <email address hidden>
    Acked-by: Frediano Ziglio <email address hidden>

 server/reds.cpp | 3 +++
 1 file changed, 3 insertions(+)

Yeah and that seems to match all that I've seen so far.
It changes the `spice_server_add_interface` which we have seen in backtraces
to now always start the QXL device if the VM is running.
Our VM is running, but the receiving QXL/Spice side is not yet.

I'll need to file a bug what we'd loose reverting this change for now until a
better coordinated start (e.g. check if the other end is ready instead of VM
running) does exist.