Bug#983319: allow to build without the udeb

[Matthias Klose]

Package: src:isc-dhcp
Version: 4.4.1-2.2
Tags: patch

allow to build the package without the udeb.
patch at
http://launchpadlibrarian.net/524431656/isc-dhcp_4.4.1-2.2ubuntu3_4.4.1-2.2ubuntu4.diff.gz