drop libkres9 and libkres-dev packages
Debian packaging as of 3.2.1-3 is no longer shipping libkres9 or libkres-dev (see https://bugs.debian.org/923970). This brings the upstream debian-style packaging in line with the Debian packaging on that front.
Signed-off-by: Daniel Kahn Gillmor dkg@fifthhorseman.net