Fix custom template tag to work with django 1.8
Fix custom template tag to work with django 1.8

jeremiak/regulations-site,tadhg-ohiggins/regulations-site,tadhg-ohiggins/regulations-site,eregs/regulations-site,18F/regulations-site,tadhg-ohiggins/regulations-site,18F/regulations-site,jeremiak/regulations-site,jeremiak/regulations-site,eregs/regulations-site,eregs/regulations-site,eregs/regulations-site,18F/regulations-site,18F/regulations-site,jeremiak/regulations-site,tadhg-ohiggins/regulations-site