workaround for nose/multiprocessing atexit bug
workaround for nose/multiprocessing atexit bug

Without this, running tests with `python setup.py test` _succeeds_, but
prints some traceback information after:

    Traceback (most recent call last):
      File "/usr/lib/python2.7/atexit.py", line 24, in _run_exitfuncs
        func(*targs, **kargs)
      File "/usr/lib/python2.7/multiprocessing/util.py", line 285, in _exit_function
        info('process shutting down')
    TypeError: 'NoneType' object is not callable

http://bugs.python.org/issue15881#msg170215

gavinwahl/sdb