(ok 2.10.2) Missing header when deleting a checked column

Report from Michael Keck. Suggested patch in tbl_structure.php:

$err_url = 'tbl_structure.php?' . PMA_generate_common_url($db, $table);
+ require_once('./libraries/header.inc.php');
+ require_once './libraries/tbl_links.inc.php';
require './libraries/mult_submits.inc.php';