GUACAMOLE-203: Tweak warning message sent to users.
GUACAMOLE-203: Tweak warning message sent to users.

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