Do not setup APT-repositories

Assume that everything (repos, keys) have been set.
Git-repos are not needed
Use ltsp-update-kernels from puavo-ltsp-bootserver
Do not install any packages

They are all assumed to be installed before this script is run.
Remove lightdm setup

lts.conf is received via tftp
Remove DNS and DHCP setup

puavo-init-bootserver-ddns sets everything.
Use /etc/puavo/hostname instead of hostname
Updating inetd and installing make_homedir is now part of puavo-ltsp-bootserver package