Clean up the basic instructions for getting started with clang to always return to the same directory.
Clean up the basic instructions for getting started with clang to always
return to the same directory.

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@161823 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang