Revert "Re-add custom changes on isc-dhcp42-server accidentally removed on b4db21e5 and unbreak php53-pfSense-module build"

dns/bind99 provide those files, since we'll need bind99 for 2.2,
requires it for other versions too

This reverts commit 5133572ccdab1ca7e6694d8204043ecc4126b0d8.
Make php pfSense module to depends of bind99 to build