fastlint: Correct concatenation of file lists
    
    `printf` ignores excessive arguments unused in formatting.
    This resulted in only the first file from two file lists was
    linted/ stylechecked if both Python template files and Python
    modules were changed.
    
    Make use of formatting instead:
    > The format is reused as necessary to consume all of the arguments
    
    Fixes: https://pagure.io/freeipa/issue/9318
    Signed-off-by: Stanislav Levin <slev@altlinux.org>
    Reviewed-By: Rob Crittenden <rcritten@redhat.com>
    Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>