Comment 2 for bug 1279645

I guess you're right. However, a lot of users won't notice that DependsOn is necessary when using external_gateway_info.

On the one hand, it's no problem without DependsOn when using OS::Neutron::RouterGateway.
I think, adding following codes to OS::Neutron::Router would avoid this problem.

https://github.com/openstack/heat/blob/master/heat/engine/resources/neutron/router.py#L273

I'm not sure what it really should add. But it's better for user experience.