Merged revisions 72572 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/trunk

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  r72572 | r.david.murray | 2009-05-11 21:36:57 -0400 (Mon, 11 May 2009) | 3 lines

  Make it clear up front that shelve only records changes
  when objects are assigned back to it when writeback is False.
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