[Python-Dev] ref leak w/except hooks

[Neal Norwitz]

The following code leaks a reference.  Original test case from
Lib/test/test_sys.py in test_original_excepthook.

import sys, StringIO
eh = sys.__excepthook__
try:
  raise ValueError(42)
except ValueError, exc:
  exc_type, exc_value, exc_tb = sys.exc_info()
  eh(exc_type, None, None)