Breaks hook_auth

Drupal's hook_auth is designed to allow multiple authentication backends to operate simultaneously. LDAP Integration hijacks the authentication workflow with a form_alter - this is fine in and of itself, but it does so in a way that hook_auth is never called (even if the user is found in neither Drupal nor LDAP data sources), meaning that other modules that would like to offer external authentication never get a chance to do this.

The simplest fix appears to be to just return flow to user_authenticate if both Drupal and LDAP data sources have come up blank. The attached patch is for Drupal 5, but having reviewed the code I am fairly sure that the issue is also in the Drupal 6 version. I am happy to roll an additional D6 patch if that would help.