"oc debug" should exit non-zero when the executed command returns non-zero

CU  uses the debug pod to create etcd-backups on all of our stages (dev/prod)

https://cloud.redhat.com/blog/ocp-disaster-recovery-part-1-how-to-create-automated-etcd-backup-in-openshift-4.x

We ran into the issue that the job ran successfully but the command inside the oc debug had an error and did not created a backup.
So to check, if the command has issues, CU would like that the debug pod pass trough the exit code of the executed command.
If an error occurred inside the debug pod we would not notice until CU check the backup manually.

Discussed here https://github.com/openshift/origin/issues/15854

Discussed previous PR here too https://github.com/openshift/origin/pull/16879