Quote path to Python executable in case it has spaces
Quote path to Python executable in case it has spaces

These days Python 3 is typically installed into C:/Program Files, so
cope with that.

Similar to r364077 in compiler-rt.

git-svn-id: a34e9779ed74578ad5922b3306b3d80a0c825546@364087 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/clang-tools-extra,llvm-mirror/clang-tools-extra,llvm-mirror/clang-tools-extra,llvm-mirror/clang-tools-extra