[Merge] ~paride/ubuntu-seeds/+git/ubuntu:revert-usm-depenency into ~ubuntu-core-dev/ubuntu-seeds/+git/ubuntu:kinetic

[Paride Legovini]

More than the change itself (which come from a clean `git revert`), please review the commit message: I tried to summarize the rationale for the revert, but I'm not fully sure I've got the whole picture right.
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https://code.launchpad.net/~paride/ubuntu-seeds/+git/ubuntu/+merge/424686
Your team Ubuntu Core Development Team is requested to review the proposed merge of ~paride/ubuntu-seeds/+git/ubuntu:revert-usm-depenency into ~ubuntu-core-dev/ubuntu-seeds/+git/ubuntu:kinetic.