Lower vpn MTU from 1426 to 1312 because of DS-Lite connections. See thread on developer mailinglist "Änderung der MTU für DS-Lite Anschlüsse"

Signed-off-by: Clemens John <clemens.john@floh1111.de>

Example:
0.5.3 < 0.5.3+0-dev
0.5.3 > 0.5.2.99+0-dev

Signed-off-by: Clemens John <clemens-john@gmx.de>

removed gluon-legacy package as it is only relevant for Hamburg/Luebeck/Kiel to upgrade from older Firmware-Versions