Fix podspec for LDProgressView [1.0]

The travis ci build failed because I was using the newer ruby has syntax. Here's a link to the [build failure](http://mandrillapp.com/track/click.php?u=30007208&id=a6b62c5b493b42019d92188380c1bf10&url=https%3A%2F%2Ftravis-ci.org%2FCocoaPods%2FSpecs%2Fbuilds%2F11957323&url_id=5ca76ac97d9bcaa67cb11f4e8db47cf794849a4b).