[Merge] lp:~evfool/update-manager/fix665173 into lp:update-manager

[Robert Roth]

I have tested it manually on a source not supporting changelogs, and the message is only shown once, as expected. Do you mean a unit-test? I think I could do that with a hard-coded launchpad changelog URL, that reports that changelogs are not supported. I'll check, I haven't written any Python unit-tests so fat, but I assume that the right place for this would be another method in the tests/test_changelog.py
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https://code.launchpad.net/~evfool/update-manager/fix665173/+merge/55663
Your team Ubuntu Core Development Team is requested to review the proposed merge of lp:~evfool/update-manager/fix665173 into lp:update-manager.