Menu Customizer: remove updateList() from availableMenuIemsPanel view. Search will eventually be done via AJAX, and was barely functional anyway. Fixes panel taking incredibly long to load (and crashing Firefox).

git-svn-id: https://plugins.svn.wordpress.org/menu-customizer/trunk@954959 b8457f37-d9ea-0310-8a92-e5e31aec5664