improve output of oc idle

[juanvallejo]

Related bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1402356

Improves the output of oc idle when idling a service with one or more scalable refs, no scalable refs (or a service that has already been idled), and when idling a service with the --dry-run flag.

Before

$ oc idle database
Marked service test-oc-idle/database to unidle resource DeploymentConfig test-oc-idle/database (unidle to 1 replicas)
Idled DeploymentConfig test-oc-idle/database

# idle a svc that has already been marked as idled
$ oc idle database
error: no scalable resources marked as idled for service test-oc-idle/database, not marking as idled

# with --dry-run, the (dry run) text did not appear if the service was already idled
$ oc idle database --dry-run
Marked service test-oc-idle/database to unidle resource DeploymentConfig test-oc-idle/database (unidle to 1 replicas)

After

$ oc idle database
The service "test-oc-idle/database" has been marked as idled
The service will unidle DeploymentConfig "test-oc-idle/database" to 1 replicas once it receives traffic
DeploymentConfig "test-oc-idle/database" has been idled

$ oc idle database
error: unable to mark the service "test-oc-idle/database" as idled.
Make sure that the service is not already marked as idled, and that it is associated with resources that can be scaled.
See 'oc idle -h' for help and examples.

$ oc idle database --dry-run
The service "test-oc-idle/database" has been marked as idled (dry run)
The service will unidle DeploymentConfig "test-oc-idle/database" to 1 replicas once it receives traffic (dry run)

cc @fabianofranz @DirectXMan12 @openshift/cli-review

[juanvallejo]

[test]

[DirectXMan12]

LGTM 👍

[openshift-bot]

Evaluated for origin test up to 9575d79

[openshift-bot]

continuous-integration/openshift-jenkins/test SUCCESS (https://ci.openshift.redhat.com/jenkins/job/test_pr_origin/13479/) (Base Commit: 92ce2c9)

[fabianofranz]

[merge]

[fabianofranz]

flaked on #12784 (comment) re[merge]

[openshift-bot]

Evaluated for origin merge up to 9575d79

[openshift-bot]

continuous-integration/openshift-jenkins/merge SUCCESS (https://ci.openshift.redhat.com/jenkins/job/test_pull_requests_origin_future/239/) (Base Commit: c8e60fe) (Image: devenv-rhel7_5920)