Mercurial no longer needed (#2237)
Mercurial no longer needed (#2237)

Inclusion broke install on Windows 10. Tested after removal.
safwanrahman/readthedocs.org,rtfd/readthedocs.org,tddv/readthedocs.org,tddv/readthedocs.org,tddv/readthedocs.org,davidfischer/readthedocs.org,rtfd/readthedocs.org,safwanrahman/readthedocs.org,davidfischer/readthedocs.org,rtfd/readthedocs.org,pombredanne/readthedocs.org,safwanrahman/readthedocs.org,rtfd/readthedocs.org,safwanrahman/readthedocs.org,pombredanne/readthedocs.org,pombredanne/readthedocs.org,davidfischer/readthedocs.org,davidfischer/readthedocs.org