Running `docker stack services <STACK> --orchestrator swarm would yield
the message "Noting found in stack: asdf" with an exit code 0. The same
command with kubernetes orchestrator would yield "nothing found in
stack: adsf" (note the lower-case "nothing") and a non-zero exit code.
This change makes the `stack services` command uniform for both
orchestrators. The logic of getting and printing services is split to
reuse the same formatting code.
Signed-off-by: Djordje Lukic <djordje.lukic@docker.com>
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>