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/Tooling/Tooling.cpp b/lib/Tooling/Tooling.cpp
index e7bfba7..4f3edf3 100644
--- a/lib/Tooling/Tooling.cpp
+++ b/lib/Tooling/Tooling.cpp
@@ -26,6 +26,7 @@
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Host.h"
+#include "llvm/Support/PathV1.h"
 #include "llvm/Support/raw_ostream.h"
 
 // For chdir, see the comment in ClangTool::run for more information.