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
Updated from global requirements

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