fuel/core — pull request #1315 by kobash (2013-02-08 08:26:56+00:00)
Title: Fix bugs in FileClass

[FileClass](https://github.com/fuel/core/blob/1.6/develop/classes/file.php) does not work if it is used with lock.
I think the problem is 'open_file()' & 'close_file()' , so I modified these functions.
Please confirm.