Comment 6 for bug 1279645

Neutron will remove router gatway when deleting router, so I think it is no needed to add client.remove_gateway_router(self.resource_id) before delete_router.

In this issue, I think heat deleted subnet before deleted router, so this router-gateway port was in used, subnet deletion was failed.

And there is still another issue that the stack creation maybe failed because create router with gateway need at least one subnet in external network.

I created this stack some times, it was failed probabilistic as heat create router before create subnet.

I think add dependence is necessary.