Enable rsync fernet rotation by default

Change-Id: I6a082f5488f50c87f4d08db9298eeab8e5825f05
Related-PROD: PROD-22285
diff --git a/keystone/server/single.yml b/keystone/server/single.yml
index 68a29a7..e1131c0 100644
--- a/keystone/server/single.yml
+++ b/keystone/server/single.yml
@@ -1,6 +1,7 @@
 classes:
 - service.keystone.server.single
 - system.linux.system.users.keystone
+- system.keystone.server.fernet_rotation.single
 parameters:
   _param:
     keystone_service_token: token