Add parameter which disables returning data from update_job
    
    As discussed in T456 and T452, we need to (as a short term workaround at least)
    be able to not return data from update_job, as it makes multiple selects on
    the Results table, which take too long. It is now ON by default, so the
    update_job() call returns just the status code and empty data.
    
    Differential Revision: https://phab.qadevel.cloud.fedoraproject.org/D333