is doubled, \r\n at line end) by stripping NNTP encoding. Exit 255 with
pointer to $HOME or $PGPPATH if pgp can't find key ring. (Probably
doesn't match the necessary error message with ViaCrypt PGP.) Failures
also report message-id so the article can be looked up to retry.
(Though I do believe news software oughtn't be unfolding them.) Checks to
ensure that the temporary file is really a file, and not a link or some
other weirdness.
