BUG/MINOR: quic: Avoid starting the mux if no ALPN sent by the client

If the client does not sent an ALPN, the SSL ALPN negotiation callback
is not called. However, the handshake is reported as successful. Check
just after SSL_do_handshake if an ALPN was negotiated. If not, emit a
CONNECTION_CLOSE with a TLS alert to close the connection.

This prevent a crash in qcc_install_app_ops() called with null as second
parameter value.
1 file changed