[DOC] Remove duplicate build of module index
[DOC] Remove duplicate build of module index

It was noticed that we had the module index built on both
the main landing page as well as on the contributor/api/index.html
page.  This patch removes the module index from the main landing
page.

Change-Id: If10286046de36da3368c8c274e6c8fd5de353fa0

openstack/cinder,Datera/cinder,Datera/cinder,eharney/cinder,openstack/cinder,phenoxim/cinder,eharney/cinder,mahak/cinder,phenoxim/cinder,mahak/cinder,j-griffith/cinder,j-griffith/cinder