Make single tenant ip version configurable

Change-Id: I92fbda78068a62bdacaa7c0d291a31c040464c18
diff --git a/ironic_tempest_plugin/tests/scenario/test_baremetal_single_tenant.py b/ironic_tempest_plugin/tests/scenario/test_baremetal_single_tenant.py
index edba601..3715608 100644
--- a/ironic_tempest_plugin/tests/scenario/test_baremetal_single_tenant.py
+++ b/ironic_tempest_plugin/tests/scenario/test_baremetal_single_tenant.py
@@ -62,7 +62,7 @@
             name=data_utils.rand_name('subnet'),
             network_id=network['id'],
             tenant_id=clients.credentials.tenant_id,
-            ip_version=4,
+            ip_version=CONF.validation.ip_version_for_ssh,
             cidr=tenant_cidr)
         subnet = result['subnet']
         clients.routers_client.add_router_interface(router['id'],