oc adm upgrade runs default case for incorrect subcommand

Description of problem:

`oc adm upgrade` silently errors out on incorrect subcommand without doing/notifying anything
this is due to the `default` case in `run()` which catches all the incorrect subcommand and runs the default part instead.

Version-Release number of selected component (if applicable): 4.10 and current

How reproducible:
use any incorrect subcommand with `oc adm upgrade`.
example: `oc adm upgrade incorrect-subcommand`

Steps to Reproduce:
1. run `oc adm upgrade incorrect-subcommand`

Actual results:
oc prints the cluster upgrade status

Expected results:
oc should error out saying incorrect subcommand