Update.php fails in 6.x-1.14, Call to undefined function content_check_update()

On a site where CCK is not installed, update 6105 fails because the functions called do not exist.

Here is a replacement function that fixes it, by checking if content module is installed first.

/**
 * Belated update for Drupal 6: Re-enable Fivestar CCK fields.
 */
function fivestar_update_6105() {
  $ret = array();

  if (!module_exists('content')) {
    $ret[] = array('success' => TRUE, 'query' => t('CCK is not installed. No need to update.'));
  }
  else {
    if ($abort = content_check_update('fivestar')) {
      return $abort;
    }

    // All CCK fields are disabled by Content module during the D6 upgrade.
    // Re-enable the Fivestar fields.
    module_load_include('inc', 'fivestar', 'fivestar_field');
    content_associate_fields('fivestar');

    $ret[] = array('success' => TRUE, 'query' => t('Re-enabled Fivestar CCK fields.'));
  }

  return $ret;
}