request_func for remove_from_load_balancer (and friends)

- [x] Mangle `supervisor.SupervisorService`
- [x] Mangle `launch_server_v1.delete_server`
- [x] Mangle `launch_server_v1.remove_from_load_balancer`
Fixed in https://github.com/rackerlabs/otter/commit/d9b65572e5d84329727ffb981a4b96d77030b945