GUAC-1389: Document VNC password retrieval.
GUAC-1389: Document VNC password retrieval.

glyptodon/guacamole-server,apache/guacamole-server,mike-jumper/incubator-guacamole-server,mike-jumper/incubator-guacamole-server,glyptodon/guacamole-server,flangelo/guacamole-server,mike-jumper/incubator-guacamole-server,glyptodon/guacamole-server,mike-jumper/incubator-guacamole-server,apache/guacamole-server,apache/guacamole-server,flangelo/guacamole-server,flangelo/guacamole-server,flangelo/guacamole-server