Preserve the original exception traceback in OrderedContainer.__setitem__.

I tried to adjust the doctest to ensure the traceback is not lost, but
as soon as I start it with a '...' (because I don't care about oldest frames),
the doctest comparator ignores everything about the traceback.

CHANGES.txt

@@ -8,6 +8,8 @@ CHANGES
 - Send ``IContainerModifiedEvent`` *after* the container is modified
   (LP#705600).
 
+- Preserve the original exception traceback in OrderedContainer.__setitem__.
+
 
 3.12.0 (2010-12-14)
 -------------------

src/zope/container/ordered.py

@@ -211,10 +211,10 @@ class OrderedContainer(Persistent, Contained):
         # This function creates a lot of events that other code listens to.
         try:
             setitem(self, self._data.__setitem__, key, object)
-        except Exception, e:
+        except Exception:
             if not existed:
                 self._order.remove(key)
-            raise e
+            raise
 
         return key