Merged revisions 85025 via svnmerge from

Merged revisions 85025 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k

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  r85025 | senthil.kumaran | 2010-09-27 06:56:03 +0530 (Mon, 27 Sep 2010) | 6 lines

  Fix Issue1595365 - Adding the req.headers after the un-redirect headers have
  been added. This helps in accidental overwritting of User-Agent header to
  default value. To preserve the old behavior, only headers not in unredirected
  headers will be updated.
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