rfc5081 update

[Nikos Mavrogiannopoulos]

I've updated the rfc5081 to conform with the new openpgp-keys
implementation of gnutls (the major change is the keyids are made
explicit in this version). It is currently on the rfc editor's queue[0],
so if there are any comments let me know as soon.

regards,
Nikos

[0].
ftp://ftp.rfc-editor.org/in-notes/internet-drafts/draft-mavrogiannopoulos-rfc5081bis-02.txt