[leafnode-list] FQDN and systemd

[Matěj Cepl]

Apparently everything has to change in the world of systemd, but 
this I have give its authors at least they provide 
well-documented nice tools. So in the brave new world of 
systemd, you are not supposed to edit and exactly write down 
values in /etc/hostname (or /etc/sysconfig/network or somewhere 
else), but rather to use hostnamectl(1).

Apparently 
https://docs.fedoraproject.org/en-US/Fedora/18/html/System_Administrators_Guide/s2_Set_All_the_Hostnames.html 
just plain

# hostnamectl set-hostname name

is what’s required.

I just thought it might be helpful to add this to 
README-FQDN.tex.

Best,

Matěj