Revise our code to only call Request.Namespace() if a namespace
*should* be present. For root scoped resources, namespace should
be ignored. For namespaced resources, it is an error to have
Namespace=="".
Scheduler uses Reflector from pkg/client/cache.
It defines some helper classes.
I'd like to use those helpers with pkg/client/cache
in kube-proxy and kubelet too.
