The hook is still called after InitialiseRFBConnection() so we can choose
the color settings depending on the vnc server (or settings) in that hook.

This way one can use the "VNC server default format" pixelformat if the
client supports it, or perform a workaround (Intel AMT KVM "classic vnc"
server only works using 8bit colors in RFB3.8)
Signed-off-by: Wouter Van Meir <wouter.vanmeir@pandora.be>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>