/**
 * Override the OPML icon, we want to hide it
 */
function foobar_opml_icon($url) {
  return '';
}

/**
 * Implementation of hook_registry_alter()
 */
function foobar_theme_registry_alter(&$theme_registry) {

  /**
   * We want to override the link paths back to blog page
   */
  $theme_registry['opml_icon']['function'] = 'foobar_opml_icon';
}