If the user has set a vnc display number both in vnclisten (with
"xxxx:yy"), and with vncdisplay, throw an error.
Update man pages to match.
Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>