test_logging sometimes fails with the following error, e.g. on the
buildbots (*):

Error in atexit._run_exitfuncs:
Traceback (most recent call last):
  File
"/home/buildbot/cpython-ucs4/trunk.pitrou-ubuntu-wide/build/Lib/atexit.py",
line 24, in _run_exitfuncs
    func(*targs, **kargs)
  File
"/home/buildbot/cpython-ucs4/trunk.pitrou-ubuntu-wide/build/Lib/logging/__init__.py",
line 1556, in shutdown
    h.flush()
AttributeError: 'NoneType' object has no attribute 'flush'
Error in sys.exitfunc:
Traceback (most recent call last):
  File
"/home/buildbot/cpython-ucs4/trunk.pitrou-ubuntu-wide/build/Lib/atexit.py",
line 24, in _run_exitfuncs
    func(*targs, **kargs)
  File
"/home/buildbot/cpython-ucs4/trunk.pitrou-ubuntu-wide/build/Lib/logging/__init__.py",
line 1556, in shutdown
    h.flush()
AttributeError: 'NoneType' object has no attribute 'flush'
[874213 refs]


(*)
http://www.python.org/dev/buildbot/all/builders/AMD64%20Ubuntu%20wide%20trunk/builds/185/steps/test/logs/stdio