Deprecate [rbac] configuration group.

The [rbac] configuration group has been deprecated
and will be removed in the next release. It has been
renamed to the [patrole] group which contains
the exact same options.

This commit makes necessary deprecation changes,
along with renaming changes to documentation, unit
tests and framework.

Change-Id: I71198506b97b98ac18a969b7e6b13b664579c081
diff --git a/doc/source/usage.rst b/doc/source/usage.rst
index 7470e9e..dff43f2 100644
--- a/doc/source/usage.rst
+++ b/doc/source/usage.rst
@@ -30,7 +30,7 @@
 To change the role that the patrole tests are being run as, edit
 ``rbac_test_role`` in the ``rbac`` section of tempest.conf: ::
 
-    [rbac]
+    [patrole]
     rbac_test_role = Member
     ...