Remove invalid attribute `exception` (#3298)
Remove invalid attribute `exception` (#3298)

* Remove invalid attribute `exception`

https://docs.djangoproject.com/en/1.9/ref/views/#django.views.defaults.server_error

This bug was introduced at https://github.com/rtfd/readthedocs.org/commit/5e0f4c0d0796476c4da9aabffca1d57fea806f57#diff-f37089595920e35da08a9395c370515eR107

* Remove linting comments

rtfd/readthedocs.org,rtfd/readthedocs.org,davidfischer/readthedocs.org,rtfd/readthedocs.org,pombredanne/readthedocs.org,davidfischer/readthedocs.org,pombredanne/readthedocs.org,safwanrahman/readthedocs.org,davidfischer/readthedocs.org,davidfischer/readthedocs.org,safwanrahman/readthedocs.org,safwanrahman/readthedocs.org,rtfd/readthedocs.org,pombredanne/readthedocs.org,safwanrahman/readthedocs.org