New tests for editing a user.

These are a large set of tests that need to be passed to allow a user
to be edited.  They are still not perfect because they assume that
anyone can edit the users, but we don't have a mechanism for logging
in and out, yet, so this will have to do.
Fix test to have correct field name

The tests checked for the Name field instead of the Username field in
one place.  This fixes the test so it remains self-consistent and also
consistent with the new user creation form.