k8sutil: cmdreporter: properly set app name
k8sutil: cmdreporter: properly set app name

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 <135b86f2968bdbcc730c10d8ababd343bb675986@suse.com>

rook/rook,rook/nfs,rook/rook,rook/rook,rook/nfs,rook/rook,rook/rook,rook/nfs