Include PathV1.h in files that use it.

This is preparation for replacing Path.h with PathV2.h.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@183781 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 6af3663..3b75790 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -29,6 +29,7 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Support/Path.h"
+#include "llvm/Support/PathV1.h"
 #include "llvm/Support/system_error.h"
 #include <sys/stat.h>
 using namespace clang;