RFC: remove traceback from "newer branch format than your bzr"

[Samuel Bronson]

At Tue, 11 Aug 2009 15:14:45 +0200,
Jelmer Vernooij wrote:

> Strack traces are the equivalent of segmentation faults in Bazaar,
> when they are displayed there is *always* a bug, never expected
> behaviour. I think hiding the detailed debug information here is a red
> herring, we should work on fixing those bugs instead.

Ever notice how on Windows, when you get an error like that, it
usually only shows you a little bit of info? You have to click on
things (or have a debugger installed) to get more out of it...

Also, even in Linux, I don't remember getting stack traces for
segfaults very often...