Disable providing keystone api_version from reclass

Related-Prod: PROD-35257
Change-Id: Iff1888d18bd66c552cafd555831a3c6d26a56571
diff --git a/keystone/client/single.yml b/keystone/client/single.yml
index 20b2b91..b69d030 100644
--- a/keystone/client/single.yml
+++ b/keystone/client/single.yml
@@ -46,6 +46,7 @@
                   options: ${_param:openstack_service_user_options}
         admin_identity:
           admin:
+            api_version: ''
             user: admin
             password: ${_param:keystone_admin_password}
             project: admin