This changes instructs the replication controller to delete replicas in the order of "unscheduled (pending)", "scheduled (pending)", and "scheduled (running)" pods. This is less disruptive than deleting random pods.
This change is to make API consistent with our convention. Fixes #3622
quantities 'CPU' and 'Memory' will be preserved until support for v1beta1 and v1beta2 APIs are dropped. Improved resource validation in the process.