[Merge] ~xnox/grub:fix-postinst-empty-devices into ~ubuntu-core-dev/grub/+git/ubuntu:ubuntu

[Michael Vogt]

Review: Approve

This looks correct to me, I will try it later today on the machine that failed originally.
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https://code.launchpad.net/~xnox/grub/+git/grub/+merge/391438
Your team Ubuntu Core Development Team is requested to review the proposed merge of ~xnox/grub:fix-postinst-empty-devices into ~ubuntu-core-dev/grub/+git/ubuntu:ubuntu.