I tested it out, and it didn't work for me....until I cleared the cache!
Just go to yoursite.com/admin/config/development/performance/ and click "clear all caches".
Update: since clearing the cache didn't work, check if you are editing the right file: delete all the code in the tpl.php file.
- If the view disappears, you are editing the right file.
- If it still shows, close your editor window and select the file again.