Instead of injecting an empty resolv.conf with an includes.chroot, we'll
inject it in late with a hook. The empty resolv.conf breaks DNS early in
the build, and causes some binary hooks to fail.
We don't want the symlink to /run/systemd/resolve/stub-resolv.conf, and
launchpad-buildd will inject its own version if it doesn't get confused by a
symlink.
