retan ActionNode _actionSpawn while create
add judgment for retaining _actionSpawn
fixed action node crash
change to use CC_SAFE_RELEASE_NULL and CC_SAFE_RETAIN
Merge pull request #3755 from liamcindy/develop_action

[ci skip]change to use CC_SAFE_RELEASE_NULL and CC_SAFE_RETAIN
revising indent Erro
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-x into develop