raise_from throws NameError when the second parameter is an exception imported via import <module>.

See this commit where I had to work around it:
nipy/nipype@ec075eb#diff-2e44cd91a342e50500957ba5eb213f41R12

I suspect the problem is with _repr_strip, but I could not confirm: https://github.com/PythonCharmers/python-future/blob/master/src/future/utils/__init__.py#L397