Redirect compute v2.1 api-ref to in-tree nova api-ref
Redirect compute v2.1 api-ref to in-tree nova api-ref

The in-tree api-ref docs in Nova are the most current
docs and are much more accurate than what's currently
in the api-ref-compute-v2.1.html page.

Change-Id: Ic26b0c9af9a507d3a768563037623b6e12703dda

openstack/api-site,openstack/api-site,openstack/api-site,openstack/api-site