use v3 api to get certificates

Let Token signing and ca certificates can be accessible at
/v3/OS-SIMPLE-CERT/{ca,certificates}.

Change-Id: I6c82d1f78ba1ff2ab110474623982542610b4d2d
Closes-Bug: #1206345
Remove releases.rst from keystone docs

The most recent update to releases.rst was made back in 2012,
but it's references in the docs page. It is providing false
(or at least, inaccurate) information. Suggest removing it
since the server side doesn't have a release related file either.

Change-Id: If2a71b55117c450afdade3cad697eba5a626263f
Merge "Remove releases.rst from keystone docs"
Updated from global requirements

Change-Id: I865b2e2fbffa2335e58e98b027b09d49f30bd00b
Merge "use v3 api to get certificates"
Merge "Updated from global requirements"