I think there were only four files I had to patch manually after running 2to3; each used automatic exception unpacking.

2to3 successfully fixes Lib/tarfile.py (as of tarfile.py r53336, 2to3 r53339).

The 'del e' in testExceptionCleanup() was indeed needed; it was there to verify that the transformation was

    except V as N:
       try:
          ...
       finally:
          N = None
          del N

and not

    except V as N:
       try:
          ...
       finally:
          del N