configure: remove help string for 'vnc-tls' option
The '--enable-vnc-tls' option to configure was removed in
commit 3e305e4a4752f70c0b5c3cf5b43ec957881714f7
Author: Daniel P. Berrange <berrange@redhat.com>
Date: Thu Aug 6 14:39:32 2015 +0100
ui: convert VNC server to use QCryptoTLSSession
This removes the corresponding help string.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>