Adding DeleteResult for v3.services.Delete
diff --git a/openstack/identity/v3/services/requests_test.go b/openstack/identity/v3/services/requests_test.go
index 337647c..32e6d1b 100644
--- a/openstack/identity/v3/services/requests_test.go
+++ b/openstack/identity/v3/services/requests_test.go
@@ -204,8 +204,6 @@
 		w.WriteHeader(http.StatusNoContent)
 	})
 
-	err := Delete(client.ServiceClient(), "12345")
-	if err != nil {
-		t.Fatalf("Unable to delete service: %v", err)
-	}
+	res := Delete(client.ServiceClient(), "12345")
+	testhelper.AssertNoErr(t, res.Err)
 }