[Merge] ~ubuntu-core-dev/shim/+git/shim-signed:xnox/dual-signed into ~ubuntu-core-dev/shim/+git/shim-signed:master

[Julian Andres Klode]

Review: Approve

Looks OK I guess, but is there even a point in shipping a single-signed shim if we have the dual-signed one?
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https://code.launchpad.net/~ubuntu-core-dev/shim/+git/shim-signed/+merge/388661
Your team Ubuntu Core Development Team is requested to review the proposed merge of ~ubuntu-core-dev/shim/+git/shim-signed:xnox/dual-signed into ~ubuntu-core-dev/shim/+git/shim-signed:master.