[Merge] lp:~juliank/ubuntu-release-upgrader/double-check-source-release into lp:ubuntu-release-upgrader

[Brian Murray]

I've added a comment to the bug report regarding fixing this a different way.
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https://code.launchpad.net/~juliank/ubuntu-release-upgrader/double-check-source-release/+merge/337258
Your team Ubuntu Core Development Team is requested to review the proposed merge of lp:~juliank/ubuntu-release-upgrader/double-check-source-release into lp:ubuntu-release-upgrader.