Refer to error_code with the std prefix.

llvm-svn: 210817
diff --git a/clang/lib/AST/InheritViz.cpp b/clang/lib/AST/InheritViz.cpp
index 84cc167..eb3020c 100644
--- a/clang/lib/AST/InheritViz.cpp
+++ b/clang/lib/AST/InheritViz.cpp
@@ -139,7 +139,7 @@
 
   int FD;
   SmallString<128> Filename;
-  error_code EC =
+  std::error_code EC =
       sys::fs::createTemporaryFile(Self.getAsString(), "dot", FD, Filename);
   if (EC) {
     llvm::errs() << "Error: " << EC.message() << "\n";