Skip updating resources that already meet the desired replica count.
This change has an impact in both kubectl scale and kubectl delete in
that reapable resources that already have the desired replicas (number
provided via --replicas for scale, or zero for delete) won't be updated
again and a "already scaled" message will be printed (in case of scale).
This commit adds support for using kubectl scale to scale deployments. Makes use of the
deployments/scale endpoint instead of updating deployment.spec.replicas directly.
