The app name was not being set in k8sutil's cmdreporter code, resulting
in jobs being labeled `app=` with no name. Change cmdreporter's `New`
method to validate the contents of the config struct and not the inputs
to the `New` method to help prevent an issue like this from creeping up
in the future.
Signed-off-by: Blaine Gardner <blaine.gardner@suse.com>