add QA:Testcase_Anaconda_updates.img_via_installation_source
    
    Summary:
    we can test this quite easily by placing the standard openQA
    updates image in the NFS repo used for the NFS repo install
    tests. We just have to copy the contents of the ISO (instead of
    directly exporting the ISO loop mount as an NFS share) so we
    can add this extra file.
    
    At first I planned to combine this with the NFS repo variation
    test, but when you use a remote stage2 like this it changes repo
    setup such that the packaging.log line we look for to verify
    the remote repo was used does not show up, and there's enough
    fuzziness in how anaconda-dracut fudges inst.repo and
    inst.stage2 that it's probably a good idea to test them
    separately anyhow.
    
    Test Plan:
    Run the new test and the other NFS tests, make sure
    this one works and the others don't break.
    
    Reviewers: jskladan, garretraziel
    
    Reviewed By: garretraziel
    
    Subscribers: tflink
    
    Differential Revision: https://phab.qadevel.cloud.fedoraproject.org/D929