oh really? hrmm

i was replicating what's found in some other `destroy` methods in **katello**.
```
$ grep -rn ":status => 204" .
./app/controllers/katello/api/v1/candlepin_proxies_controller.rb:234:      render :text => _("Deleted consumer '%s'") % params[:id], :status => 204
./app/controllers/katello/api/v1/systems_controller.rb:235:    respond :message => _("Deleted system '%s'") % params[:id], :status => 204
./app/controllers/katello/api/v2/systems_controller.rb:216:    respond :message => _("Deleted system '%s'") % params[:id], :status => 204

```