pylint: also verify scripts
    
    Build all scripts in install/tools/ to check them with pylint, so that
    ``make pylint`` always checks all scripts. The script files are
    generated by make.
    
    Please note that fastlint does not check script files.
    
    See: https://pagure.io/freeipa/issue/7772
    Signed-off-by: Christian Heimes <cheimes@redhat.com>
    Reviewed-By: Thomas Woerner <twoerner@redhat.com>
    Reviewed-By: Rob Crittenden <rcritten@redhat.com>
    Reviewed-By: Tibor Dudlak <tdudlak@redhat.com>