fix session table

@@ -21,7 +21,7 @@
 // mysql session support need create table as sql:
 //	CREATE TABLE `session` (
 //	`session_key` char(64) NOT NULL,
-//	session_data` blob,
+//	`session_data` blob,
 //	`session_expiry` int(11) unsigned NOT NULL,
 //	PRIMARY KEY (`session_key`)
 //	) ENGINE=MyISAM DEFAULT CHARSET=utf8;