Removed old includes/admin.php file

git-svn-id: https://plugins.svn.wordpress.org/wp-last-modified/trunk@751047 b8457f37-d9ea-0310-8a92-e5e31aec5664
Minor update to includes/admin.php

git-svn-id: https://plugins.svn.wordpress.org/wp-last-modified/trunk@751048 b8457f37-d9ea-0310-8a92-e5e31aec5664