Address review comment on r189557.

We need to escape filenames the same way in InclusionRewriter whether
UseLineDirective is true or false.

Review comment from http://llvm.org/bugs/show_bug.cgi?id=17018#c2

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@190834 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Rewrite/Frontend/InclusionRewriter.cpp b/lib/Rewrite/Frontend/InclusionRewriter.cpp
index 3fba690..49b23dd 100644
--- a/lib/Rewrite/Frontend/InclusionRewriter.cpp
+++ b/lib/Rewrite/Frontend/InclusionRewriter.cpp
@@ -110,7 +110,9 @@
   if (!ShowLineMarkers)
     return;
   if (UseLineDirective) {
-    OS << "#line" << ' ' << Line << ' ' << '"' << Filename << '"';
+    OS << "#line" << ' ' << Line << ' ' << '"';
+    OS.write_escaped(Filename);
+    OS << '"';
   } else {
     // Use GNU linemarkers as described here:
     // http://gcc.gnu.org/onlinedocs/cpp/Preprocessor-Output.html