Generate /etc/issue with Grml release information This file is displayed by default on systemd systems, so we want to have according Grml release information inside it (instead of e.g. "Debian GNU/Linux 9 \n \l"). Closes grml/release-planning#5 @ GH
Update /etc/grml_version in GRMLBASE script instead of grml-live [ch: Initramfs update has been moved into a GRMLBASE script, too.]