Fix back-compat plugins page redirects. Props filosofo. fixes #10246 for trunk

git-svn-id: http://svn.automattic.com/wordpress/trunk@11628 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/plugin.php

@@ -691,6 +691,9 @@ function add_submenu_page( $parent, $page_title, $menu_title, $access_level, $fi
 		add_action( $hookname, $function );
 
 	$_registered_pages[$hookname] = true;
+	// backwards-compatibility for plugins using add_management page.  See wp-admin/admin.php for redirect from edit.php to tools.php
+	if ( 'tools.php' == $parent ) 
+		$_registered_pages[get_plugin_page_hookname( $file, 'edit.php')] = true;
 
 	return $hookname;
 }