Project model should not resolve fail promise

This is for #9278 

Argh. There was a unit test for this that is disabled and I thought the problem had to do with synchronous resolution, but it was a real bug (that is fix by this change). Please:

* re-enable the test "rejects the promise when there's an error"
* delete the comment above that test
* remove xit from the `/*global` comment so that JSHint won't complain

(BTW, this is a good example of the kind of thing that can be test-driven... without the change above, you can see the test fail. Make the change and the test passes...)