It's been marked as deprecated since QEMU v2.9.0, so that should have
been enough time for everybody to either just drop unnecessary "vlan=0"
parameters, to switch to the modern -device + -netdev syntax for connecting
guest NICs with host network backends, or to switch to the "hubport" netdev
in case hubs are really wanted instead.

Buglink: https://bugs.launchpad.net/qemu/+bug/658904


Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>