upgraded gunicorn, removed deprecated flag, and added timezone to logging

Upgrade of gunicorn brings it to a version that includes timezone in access log. As far as I can tell it's working - there appear to be two bugs in running the nose tests that also exist in 0.7.3, unless I'm running it wrong.
On Tue, Aug 12, 2014 at 09:27:49AM -0700, Olivier Gambier wrote:
> > @@ -23,7 +23,7 @@
> >      app.debug = True
> >      app.run(host=host, port=port)
> >      # Or you can run:
> > -    # gunicorn --access-logfile - --log-level debug --debug -b 0.0.0.0:5000 \
> 
> Why remove the --debug switch? 

Because it's useless ;) [1,2].

[1]: https://github.com/docker/docker-registry/pull/247#issuecomment-35024804
[2]: https://github.com/docker/docker-registry/pull/247#discussion_r11696085