popsu-d7/sites/all/modules/special_menu_items/special_menu_items.install

<?php

/**
 * Implementation of hook_uninstall().
 */
function special_menu_items_uninstall() {
  variable_del('special_menu_items_nolink_tag');
  variable_del('special_menu_items_seperator_tag');
  variable_del('special_menu_items_seperator_value');
  variable_del('special_menu_items_menu_item_link');
}

/**
 * "nolink" to <nolink> and "separator" to <separator>
 */
function special_menu_items_update_7000(&$sandbox){

  //change "nolink" to <nolink>
  db_update('menu_links')
    ->fields(array(
      'link_path' => '<nolink>',
      'router_path' => '<nolink>',
    ))
    ->condition('router_path', 'nolink', '=')
    ->execute();

  //change "separator" to <separator>
  db_update('menu_links')
  ->fields(array(
    'link_path' => '<separator>',
    'router_path' => '<separator>',
  ))
  ->condition('router_path', 'separator', '=')
  ->execute();

  //we don't need this variable anymore
  variable_del('special_menu_items_menu_item_link');
}