#2947 fix inapproriate comment

conf/app.ini

@@ -199,7 +199,7 @@ INTERVAL = 60
 HOST =
 
 [session]
-; Either "memory", "file", "redis" or "mysql", default is "memory"
+; Either "memory", "file", or "redis", default is "memory"
 PROVIDER = memory
 ; Provider config options
 ; memory: not have any config yet