Globalize variables used in admin-header in case it is used in a func…

…tion. props SergeyBiryukov, fixes #16143.

git-svn-id: http://svn.automattic.com/wordpress/trunk@18526 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/admin-header.php

@@ -10,6 +10,10 @@
 if ( ! defined( 'WP_ADMIN' ) )
 	require_once( './admin.php' );
 
+// In case admin-header.php is included in a function.
+global $title, $hook_suffix, $current_screen, $wp_locale, $pagenow, $wp_version, $is_iphone,
+	$user_identity, $current_site, $update_title, $total_update_count, $parent_file;
+
 get_admin_page_title();
 $title = esc_html( strip_tags( $title ) );