[ietf-dkim] Issue 1574: fix ADSP's xml2rfc 'code'

[Stephen Farrell]

Issue description: https://rt.psg.com/Ticket/Display.html?id=1574

Thread: http://mipassoc.org/pipermail/ietf-dkim/2008q2/010385.html

Seems like the problem disappeared, I don't have the xml source
so I can't tell if the suggested <artwork> attribute was added
but the txt version looks ok.

So I guess we can close this one now.

S.