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/patrole_tempest_plugin/tests/unit/fixtures.py b/patrole_tempest_plugin/tests/unit/fixtures.py
index ed50e15..6b42949 100644
--- a/patrole_tempest_plugin/tests/unit/fixtures.py
+++ b/patrole_tempest_plugin/tests/unit/fixtures.py
@@ -61,7 +61,7 @@
     def setUp(self):
         super(RbacUtilsFixture, self).setUp()
 
-        self.useFixture(ConfPatcher(rbac_test_role='member', group='rbac'))
+        self.useFixture(ConfPatcher(rbac_test_role='member', group='patrole'))
         self.useFixture(ConfPatcher(
             admin_role='admin', auth_version='v3', group='identity'))