User relationships aren't removed when a user is deleted (not cancelled)

Once a user has been deleted, UR module have to delete all relationships associated to deleted user but it doesn't work correctly. I implemented hook_user_delete in a custom module and delete non-approved relationships associated to the deleted user. like this:

/**
 * implements hook_user_delete
 */
function YOUR_MODULE_NAME_user_delete($account) {
  //user_relationships_delete_relationship($relationship, $user);
  db_delete('user_relationships')->condition('approved', 0 , '=')->condition(db_or()->condition('requester_id', $account->uid)->condition('requestee_id', $account->uid))->execute();
}

As @sebto said we're missing a hook which has now been implemented. Also demoting the priority as this isn't critical, @d-pak please give the following a read (though understand the frustration of no response):
https://www.drupal.org/node/45111