debian/watch: Fix scan to use default versions

It has been tested using:

gbp import-orig --uscan --pristine-tar

Note to self it looks like wdune is a fork of white_dune, but this should be confirmed.

Relate-to: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1036881#16# Relate-to: https://github.com/mufti11/white_dune/issues/3# Signed-off-by: Philippe Coval rzr@users.sf.net