Backport r61468 from trunk: Improves the text of the IOError raised when open() returns EINVAL.  See issue2158.
Backport r61468 from trunk: Improves the text of the IOError raised
when open() returns EINVAL.  See issue2158.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator