Message 209921 - Python tracker

This was part of the design of the new stuff added in 3.4, so it is a bug that it doesn't work...somehow I missed implementing this detail.  The full implementation should make this a policy setting, so that a custom policy could specify its own factory.  However, since 3.4 is in beta it would be a bad time to add that to the policy.

The patch proposed here implements the required behavior by hardcoding any non-compat32 policy to use EmailMessage instead of Message in feedparser.