Login errors if you change admin password or delete admin accounts

This seems like a real bug with version 2.2 RC2, and here's how to reproduce it:

log into myPhpAdmin and delete all the administrator accounts in the database (delete all the records in the "Administrators" table)

Go to your website's catalog/admin page and try to log in.  You'll get a message that there are no admin accounts, you'll get the opportunity to make one, then log in with it.

Enter in the username and password of a new admin account, log in, then log out.  Try to log back in and I bet you can't.  I get errors galore that the user name and/or password are invalid so I started adding some debug statements to login.php.

Around line 44 of login.php, I added some statements that display some variable values to $messageStack. Here's a code snippet:
              tep_session_unregister('redirect_origin');

              tep_redirect(tep_href_link($page, $get_string));
            } else {
              tep_redirect(tep_href_link(FILENAME_DEFAULT));
            }
          }else{
$messageStack->add('gregtest1', 'error');
  }
        }else{
  $messageStack->add('gregtest2', 'error');
  $messageStack->add('username=' . $username . '<br />', 'error');
  $messageStack->add('password=' . $password . '<br />', 'error');
  $messageStack->add('check=' . $check . '<br />', 'error');
  $messageStack->add('check_query=' . $check_query . '<br />', 'error');
  $messageStack->add('query=' . $query . '<br />', 'error');
  $messageStack->add('tep_db_num_rows(check_query)=' . tep_db_num_rows($check_query) . '<br />', 'error');
}

The code that outputs 'gregtest2' is getting called.  One thing that's completely strange is that $check_query has the value of "Resource id #29" all the time!  Where is that coming from?  tep_db_num_rows($check_query) is 0 which is not good... it's supposed to be 1.

Another weird thing is that if I press the Login button again, $username and $password are blank no matter what I put in there.