ietf-nntp RFC977bis w.r.t. authentication

[Brian Kantor]

I'd rather see "AUTHINFO SASL" than "AUTHINFO GENERIC".  Why not call it
what it really is?  It wouldn't surprise me to see the generic authentication
protocol change some time in the future either, so that's a bit of preparation.
When it happens, we'll use "AUTHINFO SPQR" or whatever.

And leaving AUTHINFO USER/PASS in lets the rest of the world get on with
what it's doing, for those few sites that actually implement NNTP security
beyond ipaddr and domain restrictions.  Deprecate it to be sure, but do
document and allow it.
	- Brian