Add a test for admin resetting a password

Admins can reset a password.  This adds a test to the
test framework for making sure admins can successfully
reset passwords.

Affects PR #210.
Prevent multiple callbacks in utils

As a precaution, return when doing the callback to
prevent execution from continuing.  This prevents
the same callback from being called multiple times.
Fix 2 bugs in resetPassword test

The test needs to specify `id` instead of `userId`.

The test also needs to log in with the user, not the
admin, to verify the correct password was changed.
Merge pull request #211 from 18F/fix-pr-210

Add test for previous commit: password reset fix