TECH-ERROR: Name of SPF2 record

I'm against including the major version number of the protocol in the
name of the RR type.  The '2' should not be there.

_If_ the designers of a future standard decide they need a new
typecode, they are free to do so.

But I think versioning a protocol in the typecode is probably a bad
idea, and doing so from the outset doubly so.

I propose that the record simply be called SPF.

      -roy