Add the /usr/share/live/build/data/debian-cd/kali symlink that is currently manually created by Kali's build_all.sh script.

Fix binary_debian-installer step to use linux-image-* metapackages instead of linux-image-2.6-* which are gone.

Otherwise users opting for XFS and JFS and installing without network
won't have them and the (first) boot can be interrupted due to this.