fixed #2269 Switch shader of cc.Sprite when call setTexture(null)
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-html5 into Iss2269_FixBugForLabelTTF
Merge pull request #964 from dingpinglv/Iss2269_FixBugForLabelTTF

fixed #2269 Switch shader of cc.Sprite when call setTexture(null)