[Merge] livecd-rootfs:uc18-kassel into livecd-rootfs:ubuntu/master

[Michael Hudson-Doyle]

Seems OK I guess. Were you after some deeper kind of review?

I don't know if handling subarch specific lists of snaps by having them hardcoded in livecd-rootfs is really the way to go, but I'm not sure what would be better (something something seeds?)
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https://code.launchpad.net/~ubuntu-core-dev/livecd-rootfs/+git/livecd-rootfs/+merge/366327
Your team Ubuntu Core Development Team is requested to review the proposed merge of livecd-rootfs:uc18-kassel into livecd-rootfs:ubuntu/master.