Merge duplicated renos of identity-clients

Before releasing Tempest 12.2.0, we found the duplicated renos on
http://docs.openstack.org/releasenotes/tempest/unreleased.html
That seems unreadable for users, so let's merge them into a single.

Change-Id: Id51ecebcbf56c5e0f62e3bd35e7d531f411904db
2 files changed