Update add_user command for narrowed localhost exception.
Update the rake tasks file to work under the narrowed localhost exception
Helper methods to support the narrowed localhost exception
Localhost exception fixes for functional tests
Localhost exception fixes for threading tests
Use OrderedHash for db_eval test helper
Add authentication necessary for replication tests
Rename add_admin_user to ensure_admin_user everywhere
Authentication tests should attempt to use an existing admin user first.
Localhost exception fixes for replica_set tests
clear_admin_user should be resilient to being called twice.
Replace hard-wired 13 with constant AUTH_ERROR
Fix admin user to include pre-2.6 roles
Update sharding tests to handle narrowed localhost exception
Restructure ensure_auth method so it does not affect pre-2.7.1 servers