PR#3754: Unify behavior when result is empty in get_maven/image/win/build
    
    Merges #3754
    https://pagure.io/koji/pull-request/3754
    
    Fixes: #3753
    https://pagure.io/koji/issue/3753
    Unify behavior for empty result in get_maven_build as get_image_build and get_win_build