Patch #1537 from Chad Austin

Change GeneratorExit's base class from Exception to BaseException
(This time I'm applying the patch to the correct sandbox.)

Lib/test/test_generators.py

@@ -1658,6 +1658,19 @@ And finalization:
 exiting
 
 
+GeneratorExit is not caught by except Exception:
+
+>>> def f():
+...     try: yield
+...     except Exception: print 'except'
+...     finally: print 'finally'
+
+>>> g = f()
+>>> g.next()
+>>> del g
+finally
+
+
 Now let's try some ill-behaved generators:
 
 >>> def f():