Description of problem:
When trying to delete running job, it only return: Jobs deleted:  . It should show the reason why failed to delete
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Submit a job (J:491)
2. bkr job-delete J:491
Jobs deleted: 
Show the reason why failed to delete this job, maybe it's running , or users don't have permission.