Include PathV1.h only where it is used.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@184090 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Driver/WindowsToolChain.cpp b/lib/Driver/WindowsToolChain.cpp
index 64625ed..da914be 100644
--- a/lib/Driver/WindowsToolChain.cpp
+++ b/lib/Driver/WindowsToolChain.cpp
@@ -18,6 +18,7 @@
 #include "llvm/Option/ArgList.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Path.h"
+#include "llvm/Support/PathV1.h"
 
 // Include the necessary headers to interface with the Windows registry and
 // environment.