[daemon] security: hide certificate exchange
Issue generated from Tuleap's migration script. Originally submitted by: Guillaume Roguez (guillaume)
During DLTSv1.2 session establishement for a call, the certificate is transmit in clear text over the socket.
Even if certificate are public, and obtain through opendht,
this leak information that you want to make a secure connection
to the owner of this certificate at a specific moment.
A step to more anonymous communication is to use an anonynous authentication, then process certificate authentication over it, as explain here: http://www.gnutls.org/manual/gnutls.html\#Anonymous-authentication