lxdm: bugfixes by updating to latest git

* make keyboard layout combobox display languages properly
* systemd-support is included mainline
* autologin for timeouts < 5s works as expected

Signed-off-by: Andreas Müller <schnitzeltony@googlemail.com>
Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>