Differently named symbols between OpenSSL and RFC

[J Decker <d3ck0r@xxxxxxxxx>]

I made this issue on LibreSSL's github... 

https://github.com/libressl-portable/portable/issues/537 

It's about ...

TLSEXT_TYPE_psk_kex_modes:

from openssl/tls1.h 1.1.1b

# define TLSEXT_TYPE_psk_kex_modes               45

from libressl/2.9.2 tls1.h

#define TLSEXT_TYPE_psk_key_exchange_modes	45

They argue that the names they defined follow the RFC

https://tools.ietf.org/html/rfc8446#section-4.2

 pre_shared_key(41), psk_key_exchange_modes(45), 

are what the names should be based on, and that OpenSSL's definition is also inaccurate

TLSEXT_TYPE_psk_kex_modes
 TLSEXT_TYPE_psk

https://github.com/openssl/openssl/blob/master/include/openssl/tls1.h#L143-L147  

instead of 'pre_shared_key' and 'key_exchange_modes'

(sorry, this looks kind of ragged, get what I'm sayin?)