Password Reset Option is Confusing for those using External Authentication

When you go to your "My Preferences" and click on the Password tab you get a screen which appears to allow you to change your password.  If you are using external authentication (via CAS/LDAP, Twitter, etc.) any password change you make within OAE will not actually change your password in the external system.  We have had confusion on this for similar reasons in Sakai when we left the internal "password reset" option in place.  I'm not sure if it would be possible to have that feature get de-activated if you are not using internal OAE authentication, might be something to consider.
This test wasn't working, but was succeeding because `#preferences-tab-password` didn't exist at all. I've pushed a fix for this test.