Add missing tests to nighly runs
    
    Run test_customized_ds_config_install and test_dns_locations in nightly
    runs.
    
    See: https://pagure.io/freeipa/issue/7743
    Signed-off-by: Christian Heimes <cheimes@redhat.com>
    Reviewed-By: Florence Blanc-Renaud <frenaud@redhat.com>