Windows/Path.inc: Move <shlobj.h> after "Windows.h" for some API available.

  I found that swapping the order of some header files helped fix a
  build issue that we're seeing on mingw32. Without the swap, windows.h
  was being included before _WIN32_WINNT was being defined and the
  CreateHardLinkW function was #ifdef'd out.

  It looks like the header is mainly used to get the SHGetFolderPathW
  function, so I don't think that there'll be much fallout from the
  switch.

Suggested by Alex Crichton. Thanks!

llvm-svn: 201230