更新Pod到最新版本
You can check your current version:
pod --version
0.28.0Since CocoaPods is a ruby gem you can update it, and all other installed gems, just by:
gem update
On OS X 10.9 you might have to install the Xcode command line developer tools, those are a prerequisite for the whole Ruby shebang to work.
The fastest method to install them, thanks to yanzv for pointing this out.
xcode-select --install
gem clean .只删除旧版本Pod
原文：http://www.cnblogs.com/chinaxxren/p/3523200.html