Make all tests green

On second thought... I'm going to limit the test to "Admin creates new user" and just ensure that succeeded. At one point we were having trouble logging in with users that were created through ActiveAdmin and that's why we have this circuitous test. But it's a lot to be going on for one test, and the real problem was somewhere underneath. I think it has since been resolved (although I don't remember how).

Regardless, I don't think the "user created by admin can log in" test belongs here. Instead, tests for logging in **all** permutations of User should be in a user-specific spec, using factories (and not capybara) to create the User permutations.