@Anwar hmm yes it is an answer, not necessarily an upvotable one grin I was hoping you would explain how that would work, I thought maybe that person messed up their system and then fixed it, which is not necessarily what happened to OP?
What I thought was the answerer installed xenial packages in trusty and removing them fixed the problem. I didn't think the question was 2 years ago and now I noticed that answer was posted on Sep 20!