signoff on commits for mass rebuild
    
    with pagure on dist-git pkg owners can enable a toggle switch to
    require all commits be signed off on. as per Developer Certificate
    of Origin (https://developercertificate.org/) it is good behaviour
    anyway. With a question being raised already in a pagure issue over
    using the feature to block mass rebuild builds
    https://pagure.io/pagure/issue/2459
    
    Signed-off-by: Dennis Gilmore <dennis@ausil.us>