It turns out test_curses can fail in a 2.6 buildbot because stdout is not

It turns out test_curses can fail in a 2.6 buildbot because stdout is not
a tty in certain cases.

Merged revisions 75518 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk

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  r75518 | r.david.murray | 2009-10-19 12:01:28 -0400 (Mon, 19 Oct 2009) | 3 lines

  Only run test_curses when sys.__stdout__ is a tty.  This eliminates the
  last false positive when running regrtest with -j.
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