make deb (or debuild -B) fails without CHANGES file

[Graham Percival]

I tried making a .deb with a freshly unpacked lilypond 1.6.4, both with
"debuld -B", "dch -p -v 1.6.4-0.local.1 "Local Build"; debuild -B", and
with make deb.  In all cases, it died right and the end with something
like:
----
dh_installemacsen
dh_installchangelogs -k CHANGES
error: cannot find CHANGES
-----

Then I did "touch CHANGES" in both the top level of the lilypond source
tree and in the debian/ dir.  After that "make deb" was successful.

HTH,
- Graham