BUG: ssl: mark the connection as waiting for an SSL connection during the handshake

BUG: ssl: mark the connection as waiting for an SSL connection during the handshake

The WAIT_L6_CONN was designed especially to ensure that the connection
was not marked ready before the SSL layer was OK, but we forgot to set
the flag, resulting in a rejected handshake when ssl was combined with
accept-proxy because accept-proxy would validate the connection alone
and the SSL handshake would then believe in a client-initiated reneg
and kill it.