[Patches] fix for bug open/81

[Guido van Rossum]

Just wanted to note that I think that I'm not keen on doing
PyErr_Fetch() and PyErr_Restore() -- it's slower etc.  Lots of things
can cause an indirect call to PyErr_Clear() -- the assumption simply
shouldn't be made that one can call anything while an exception is
being passed down.  The one exception is DECREF: this will never
affect the exception status (and will use Fetch/Restore when needed to
guarantee this).

--Guido van Rossum (home page: http://www.python.org/~guido/)