ZipFile.__del__() when there was an IOError opening the underlying
file in ZipFile.__init__().
This is an odd test: since the exception is in the __del__() method,
it is not propogated. This test will trigger it but regrtest.py
does not detect the failure (not sure why); we are dependent on it
actually being noticed by a user to get a new bug report if it ever
fails. ;-(
On the other hand, this makes sure that code gets exercised, so
a failure could be noticed!