Duplicate error message

Shows duplicate error message when the search404_error_message() is called twice inside search404_page(). I'm using custom search so for me it's called on lines #162 and #219 inside [search404.page.inc].

Change the drupal_set_message() line to include FALSE as the third argument.

function search404_error_message($keys) {
  if (!variable_get('search404_disable_error_message', FALSE)) {
    drupal_set_message(t('The page you requested does not exist. For your '
            . 'convenience, a search was performed using the query'
            . ' @keys.', array('@keys' => $keys)), 'error', FALSE);
  }
}