According to http://tigervnc.org/cgi-bin/rfbproto#zlib-encoding


zlib encoding only uses a single stream. Current implementation defines
4 streams but only uses the first one. Remove them and only use a single
stream.

Signed-off-by: Corentin Chary <corentincj@iksaif.net>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>