Comment 9 for bug 316272

The attached branch <https://code.edge.launchpad.net/~mbp/launchpad/dkim/+merge/26284> now has something that just might work, including some credible tests. The tests have a canned RSA key and they monkeypatch DNS to pretend it's the key for example.canonical.com.

I hit and fixed some bugs in dkim.py: when signing it generates something that's not precisely either a Simple mode or Relaxed mode signature. This patch fixes it a bit. In light of it being just one file perhaps we should just put it in the tree?