Fixed a build error in Xcode 6.1 Beta 1. Change is comparable with Xcode 6 GM.
Fixed a build error in Xcode 6.1 Beta 1. Change is comparable with Xcode 6 GM.

rain1988/json-swift,ihugang/json-swift,colemancda/json-swift,zhaoguohui/json-swift,colemancda/json-swift,owensd/json-swift,owensd/json-swift,ihugang/json-swift,rain1988/json-swift