Lifetime Markers do not exhibit proper variance used certain ways

[Ericson2314]

See http://is.gd/KdHumF . Only the third block triggers the borrow error, when presumably all three should.

[kmcallister]

Nominating.

[nikomatsakis]

Hmm, on my variance branch, I get 3 errors.

[nikomatsakis]

But on master I do not. Not sure what bug I fixed there :P