[Twisted-Python] revert

[Jason Litzinger]

On Sat, Nov 18, 2017 at 10:59:52PM -0800, Glyph wrote:
> https://twistedmatrix.com/trac/ticket/9280#comment:7 <https://twistedmatrix.com/trac/ticket/9280#comment:7> introduced a pretty serious regression (tracebacks are no longer printed by twisted.web) - can someone please do the appropriate dance to revert this and reopen the ticket?  It looks like the directions need updating for git :-).
To follow up, there is quite a bit of discussion in the ticket about this, for anyone
to whom this is of interest.

Cheers,
-Jason