Add failing test with bad message

We incorrectly state that some errors were "Caused by redirect" when they aren't, for example if you retry and get a 500 a few times in a row. 

This adds a failing test to demonstrate this. Not sure how you'd like to handle it, I don't have great suggestions at the moment but I'll keep looking.
if the response is none. hmm, i also wanted to check response.status for
None, so maybe not the best way to do it


--
Kevin Burke
phone: 925.271.7005 | twentymilliseconds.com

On Tue, Sep 30, 2014 at 3:41 PM, Andrey Petrov <notifications@github.com>
wrote:

> In urllib3/util/retry.py:
>
> >              _observed_errors += 1
> > +            try:
> > +                cause = 'received %s server error too many times' % response.status
> > +            except Exception:
>
> What's going on here? Why the except Exception? Where is the exception
> coming from?
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/shazow/urllib3/pull/464/files#r18252365>.
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