[ci skip] Add a note about sess_table_name
diff --git a/system/libraries/Session/drivers/Session_database_driver.php b/system/libraries/Session/drivers/Session_database_driver.php
index d378d53..42ff96b 100644
--- a/system/libraries/Session/drivers/Session_database_driver.php
+++ b/system/libraries/Session/drivers/Session_database_driver.php
@@ -104,6 +104,7 @@
 			$this->_platform = 'postgre';
 		}
 
+		// Note: BC work-around for the old 'sess_table_name' setting, should be removed in the future.
 		isset($this->_config['save_path']) OR $this->_config['save_path'] = config_item('sess_table_name');
 	}