[Merge] ~mwhudson/livecd-rootfs/+git/livecd-rootfs:netboot-signed-shim into livecd-rootfs:ubuntu/master

[Michael Hudson-Doyle]

This is part of https://code.launchpad.net/~mwhudson/livecd-rootfs/+git/livecd-rootfs/+merge/426680 now.
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https://code.launchpad.net/~mwhudson/livecd-rootfs/+git/livecd-rootfs/+merge/426335
Your team Ubuntu Core Development Team is requested to review the proposed merge of ~mwhudson/livecd-rootfs/+git/livecd-rootfs:netboot-signed-shim into livecd-rootfs:ubuntu/master.