Comment # 23 on bug 1209594 from Giorgio Gallo

This one "works on my machine": I put it into my /usr/etc/X11/xdm/ and, after
rebooting, my keyboard settings still survive.

It must be noted that, if XKBLAYOUT is set, /etc/vconsole.config is now
consistently rewritten twice at every boot (first "localectl set-keymap ..."
mangles it just as it did before, and then "localectl set-x11-keymap ..."
restores it to what it was).

Also... the script's logic is now even more unnecessarily convoluted now than
it was before :)