If an adaptive encoding has choosen to send a lossy update
based on the result of vnc_update_freq(), then it should advertise
it with vnc_sent_lossy_rect(). This will allow to automatically refresh
this rect once it's static again.
Signed-off-by: NCorentin Chary <corentincj@iksaif.net>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>