Fix bug when delayPerUnit was already set, but gets overridden by value in first frame. 
Fix bug when delayPerUnit was already set, but gets overridden by value in first frame. 

Former-commit-id: d178d46309e7847300d57be3cac022b2d5da1fc7
nader-eloshaiker/cocos2d-objc,zaneLou/cocos2d-objc,yaoxiaoyong/cocos2d-objc,finthamoussu/cocos2d-objc,TukekeSoft/cocos2d-spritebuilder,tambarskjelve/cocos2d-objc,liduanw/cocos2d-objc,TukekeSoft/cocos2d-spritebuilder,tambarskjelve/cocos2d-objc,TukekeSoft/cocos2d-spritebuilder,richardgroves/cocos2d-iphone,codepython/cocos2d-objc,SuPair/cocos2d-objc,DNESS/cocos2d-objc,liduanw/cocos2d-objc,cogddo/cocos2d-objc,seem-sky/cocos2d-swift,cocos2d/cocos2d-objc,tambarskjelve/cocos2d-objc,finthamoussu/cocos2d-objc,jason-puck/cocos2d-iphone,cocos2d/cocos2d-objc,nader-eloshaiker/cocos2d-objc,seem-sky/cocos2d-swift,codepython/cocos2d-objc,codepython/cocos2d-objc,tambarskjelve/cocos2d-objc,DNESS/cocos2d-objc,lpeancovschi/cocos2d-objc,yaoxiaoyong/cocos2d-objc,jason-puck/cocos2d-iphone,oxeron/cocos2d-objc,knight2010/cocos2d-objc,yaoxiaoyong/cocos2d-objc,dnessorga/cocos2d-objc,zaneLou/cocos2d-objc,richardgroves/cocos2d-iphone,seem-sky/cocos2d-swift,finthamoussu/cocos2d-objc,zaneLou/cocos2d-objc,lpeancovschi/cocos2d-objc,SuPair/cocos2d-objc,codepython/cocos2d-objc,yaoxiaoyong/cocos2d-objc,SuPair/cocos2d-objc,lpeancovschi/cocos2d-objc,dnessorga/cocos2d-objc,jason-puck/cocos2d-iphone,tambarskjelve/cocos2d-objc,savysoda/cocos2d-objc,yaoxiaoyong/cocos2d-objc,dnessorga/cocos2d-objc,DNESS/cocos2d-objc,seem-sky/cocos2d-swift,nader-eloshaiker/cocos2d-objc,lpeancovschi/cocos2d-objc,cogddo/cocos2d-objc,SuPair/cocos2d-objc,nader-eloshaiker/cocos2d-objc,finthamoussu/cocos2d-objc,liduanw/cocos2d-objc,cogddo/cocos2d-objc,DNESS/cocos2d-objc,zaneLou/cocos2d-objc,richardgroves/cocos2d-iphone,cogddo/cocos2d-objc,savysoda/cocos2d-objc,TukekeSoft/cocos2d-spritebuilder,knight2010/cocos2d-objc,dnessorga/cocos2d-objc,SuPair/cocos2d-objc,liduanw/cocos2d-objc,knight2010/cocos2d-objc,oxeron/cocos2d-objc,knight2010/cocos2d-objc,savysoda/cocos2d-objc,liduanw/cocos2d-objc,savysoda/cocos2d-objc,dnessorga/cocos2d-objc,DNESS/cocos2d-objc