deprecated gnutls_certificate_type_set_priority

[Ethan Blanton]

Mark Doliner spake unto us the following wisdom:
> I don't know the answer to this.  The only two GNUTLS_CRT_ values in
> my /usr/include/gnutls/gnutls.h are GNUTLS_CRT_X509 and
> GNUTLS_CRT_OPENPGP.  It seems mildly strange that we would exclude
> opengpg... but I'm really not familiar with this code.

This is probably because nobody has ever, in the history of the world,
created an OpenPGP certificate and used it to protect a TLS
connection.  ;-)

Ethan