If user executes `oc infinispan delete` nothing happens. Since it isn't technically a valid command as it's missing subcommand it should fail with corresponding message. Commands that do not print output upon execution are generally considered as successful.

The help for delete command should also make it clear that subcommand is required.

$ ./oc infinispan delete
$ ./oc infinispan delete -h
Usage: kube delete [<options>]
Deletes a resource

Options:
  -h, --help

delete commands:
    cluster  Deletes a cluster