Ensure to_dict() returns auth_tok

* ReddwarfContext was changed to defer to the parent's to_dict method.
  When the context is serialized to amqp, it is known by the key 'auth_token'
  instead of the expected 'auth_tok' as a side-effect.

fixes bug 1152827

Change-Id: I8fcdb2a3eaf8da0dda3c0229b24e32f528353619

reddwarf/common/context.py

@@ -50,6 +50,7 @@ class ReddwarfContext(context.RequestContext):
         parent_dict = super(ReddwarfContext, self).to_dict()
         parent_dict.update({'limit': self.limit,
                             'marker': self.marker,
+                            'auth_tok': parent_dict['auth_token'],
                             })
         return parent_dict