[debian] let dh_python autodetect dependencies

Add a mapping for cubicweb which is not part of debian.

debian/control

@@ -17,8 +17,6 @@ Package: cubicweb-ckeditor
 Architecture: all
 Section: oldlibs
 Depends:
- cubicweb-common (>= 3.24.0),
- python-six (>= 1.4.0),
  python-cubicweb-ckeditor(= ${source:Version}),
  ${misc:Depends}
 Description: transitional package

debian/pydist-overrides

+cubicweb python-cubicweb