1243 Error when a controller derives from another having a default route with name
This is because in the current implementation, the RouteAttribute on the controllers are inherited.
Thus, when the base controller is a concrete class the same route declared on the base controller is added twice (once for the base controller, and once again for the derived controller).
With this change, we no longer inherits the attribute from the base controller which is consistent with the behavior of RouteAttribute declared on the actions.