We implement a HTTP-only server here (that is wrapped by stunnel for
HTTPS support), so if a TLS handshake reaches us it is always wrong
and we can just close the connection immediately instead of accepting
it and letting the client run into a timeout as we will never receive
the message(s) we expect.
This happens e.g. with browsers like Firefox that opportunistically
try https first (even if you ask for http and specify a port).