zendframework/zf2 — pull request #2002 by sasezaki (2012-07-26 17:43:16+00:00)
Title: [Captcha][ZF-11858] sync svn r24821 

[r24821](http://framework.zend.com/code/revision.php?repname=Zend+Framework&path=%2Ftrunk&rev=24821) 2012-05-29T14:54:50.626607Z

ZF-11858: Fix possible fatal error when Zend_Captcha_Image garbage collection runs multiple times in parallel