[Merge] ~waveform/livecd-rootfs:fix-swapfile into livecd-rootfs:ubuntu/master

[Dave Jones]

> This seems okay. I usually don't like bundling fixes together as it breaks
> visibility of the issue we want to fix, but here it's fine. Left a small
> question inline below.

Yes, I figured it might be a bit controversial bundling all this together, but that's why I split it into two commits which can be easily separated/rebased should you wish. I'm happy to chop out a bit if you want?
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https://code.launchpad.net/~waveform/livecd-rootfs/+git/livecd-rootfs/+merge/415625
Your team Ubuntu Core Development Team is requested to review the proposed merge of ~waveform/livecd-rootfs:fix-swapfile into livecd-rootfs:ubuntu/master.