update block storage 'Delete' acceptance tests to use 'Extract'
diff --git a/acceptance/openstack/blockstorage/v1/volumes_test.go b/acceptance/openstack/blockstorage/v1/volumes_test.go
index d2281e6..b2f2600 100644
--- a/acceptance/openstack/blockstorage/v1/volumes_test.go
+++ b/acceptance/openstack/blockstorage/v1/volumes_test.go
@@ -47,8 +47,8 @@
 		if err != nil {
 			t.Error(err)
 		}
-		res = volumes.Delete(client, cv.ID)
-		if res.Err != nil {
+		err = volumes.Delete(client, cv.ID).Extract()
+		if err != nil {
 			t.Error(err)
 			return
 		}