[1.6.x] Fixed reference to pk in RedirectView.get_redirect_url doc.

            pattern_name = 'article-detail'

            def get_redirect_url(self, *args, **kwargs):

                article = get_object_or_404(Article, pk=pk)

                article = get_object_or_404(Article, pk=kwargs['pk'])

                article.update_counter()

                return super(ArticleCounterRedirectView, self).get_redirect_url(*args, **kwargs)