Deployment guide index: link disappears in narrow windows

[Brian Moss]

At certain window widths, the "Documentation treated like code, powered by the community - interested?" and "How To Contribute" elements move beside the list of deployment guides. This causes the guide link to become unresponsive when moused over.

Affects:

https://docs.openstack.org/project-deploy-guide/newton/
https://docs.openstack.org/project-deploy-guide/ocata/

Does not affect:

https://docs.openstack.org/project-deploy-guide/draft/

The draft index page appears to have the correct behavior. The two other elements move below the links to the deployment guides, and the links work correctly on mouse over.