atomic: run ostree write commands as apache user
    
    The files in the ostree repo are owned by apache so we need to either
    run our commands as the apache user or chown the files after they get
    created. Let's try running as the apache user first. This works from
    my local tests, we'll see about production.
    
    Signed-off-by: Dusty Mabe <dusty@dustymabe.com>