While Andrew S. Tanenbaum has a point by saying "Never underestimate the
bandwidth of a station wagon full of tapes hurtling down the highway",
we don't support that way of transportation in QEMU yet, so replace the
typo with the correct word "vlan".
Signed-off-by: Thomas Huth <thuth@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Laurent Vivier <lvivier@redhat.com> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>