When the user clicks their email validation link, a userid and a
token are sent in the querystring. However, in line 160 of
mediagoblin/auth/views.py, we are redirecting according to the
'username' session variable.

If the user is not logged in, the following traceback ensues:

::

    ----------------------------------------
    Exception happened during processing of request from ('50.15.244.85', 2850)
    Traceback (most recent call last):
      File "/home/ubuntu/src/mediagoblin/eggs/Paste-1.7.5.1-py2.6.egg/paste/httpserver.py", line 1068, in process_request_in_thread
        self.finish_request(request, client_address)
      File "/usr/lib/python2.6/SocketServer.py", line 320, in finish_request
        self.RequestHandlerClass(request, client_address, self)
      File "/usr/lib/python2.6/SocketServer.py", line 615, in __init__
        self.handle()
      File "/home/ubuntu/src/mediagoblin/eggs/Paste-1.7.5.1-py2.6.egg/paste/httpserver.py", line 442, in handle
        BaseHTTPRequestHandler.handle(self)
      File "/usr/lib/python2.6/BaseHTTPServer.py", line 329, in handle
        self.handle_one_request()
      File "/home/ubuntu/src/mediagoblin/eggs/Paste-1.7.5.1-py2.6.egg/paste/httpserver.py", line 437, in handle_one_request
        self.wsgi_execute()
      File "/home/ubuntu/src/mediagoblin/eggs/Paste-1.7.5.1-py2.6.egg/paste/httpserver.py", line 287, in wsgi_execute
        self.wsgi_start_response)
      File "/home/ubuntu/src/mediagoblin/eggs/Paste-1.7.5.1-py2.6.egg/paste/urlmap.py", line 203, in __call__
        return app(environ, start_response)
      File "/home/ubuntu/src/mediagoblin/eggs/Beaker-1.5.4-py2.6.egg/beaker/middleware.py", line 152, in __call__
        return self.wrap_app(environ, session_start_response)
      File "/home/ubuntu/src/mediagoblin/mediagoblin/app.py", line 141, in __call__
        return controller(request)(environ, start_response)
      File "/home/ubuntu/src/mediagoblin/mediagoblin/auth/views.py", line 160, in verify_email
        user=request.user['username'])
    TypeError: 'NoneType' object is unsubscriptable
    ----------------------------------------

It should be possible to edit the title, description, slug and
maybe other things.

In the long run, it might be needed to even replace the media. But
this is probably another item.