Don't use a hardcoded domain name in media_url
Don't use a hardcoded domain name in media_url

Fixes #2210

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