smtplib.starttls() needs to include does_esmtp=0. Without 
this, the "size=" suffix on MAIL FROM lines causes server 
errors since the MTA defaults to HELO mode. This is also 
necessary in order to conform to RFC 2487 section 5.2, 
which states after TLS is started, all prior knowledge 
(including esmtp capability) must be discarded.

This bug exists in Python 2.3.2 and earlier.