[Merge] ~mwhudson/livecd-rootfs/+git/livecd-rootfs:minimal-server-layer-3 into livecd-rootfs:ubuntu/master

[Didier Roche]

Review: Needs Information

Some questions on the layer choices and if we can use the live pass helpers. Otherwise good :)
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https://code.launchpad.net/~mwhudson/livecd-rootfs/+git/livecd-rootfs/+merge/406342
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