bdecode was already gone in email 5. This merge adds the test from

bdecode was already gone in email 5.  This merge adds the test from
the trunk patch, and removes the last trace of bdecode, which was
a commented out call in message.py.

Merged revisions 78778 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk

........
  r78778 | r.david.murray | 2010-03-07 21:04:06 -0500 (Sun, 07 Mar 2010) | 9 lines

  Issue #7143: get_payload used to strip any trailing newline from a
  base64 transfer-encoded payload *after* decoding it; it no longer does.
  email had a special method in utils, _bdecode, specifically to do this,
  so it must have served a purpose at some point, yet it is clearly wrong
  per RFC.  Fixed with Barry's approval, but no backport.  Email package
  minor version number is bumped, now version 4.0.1.

  Patch by Joaquin Cuenca Abela.
........