[Rakefile] Robustness against different version of xcode.
[Rakefile] Robustness against different version of xcode.

ashfurrow/CocoaPods,vivekshukla-mob-ibtech/Repository,mglidden/CocoaPods,segiddins/CocoaPods,orta/CocoaPods,mglidden/CocoaPods,0xced/CocoaPods,Ashton-W/CocoaPods,mglidden/CocoaPods