hook_access doesn't play well with others

The current implementation of webform_access() returns FALSE if the user doesn't have permission (according to Webform). Instead, it should only return TRUE if the user does have permission, otherwise return nothing. That way, other modules can grant access by way of the node_access table if they feel it's appropriate. See the attached patch, and the docs:

http://api.drupal.org/api/function/hook_access/6