Pass arguments to tweak to build

Usage :
./build-libssl.sh [version] [Xcode path]

Example :
./build-libssl.sh 1.0.1h /Applications/Xcode-6.0.1.app

By default Xcode is in /Applications/Xcode.app :
./build-libssl.sh 1.0.1h /Applications/Xcode.app
is equivalent to
./build-libssl.sh 1.0.1h