Reverts third_party/protobuf: Update to HEAD (f52e188fe4)

third_party/protobuf/src/google/protobuf/reflection_ops.h

 // Protocol Buffers - Google's data interchange format
 // Copyright 2008 Google Inc.  All rights reserved.
 // https://developers.google.com/protocol-buffers/
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
@@ skipping 49 matching lines @@
   static void Merge(const Message& from, Message* to);
   static void Clear(Message* message);
   static bool IsInitialized(const Message& message);
   static void DiscardUnknownFields(Message* message);
 
   // Finds all unset required fields in the message and adds their full
   // paths (e.g. "foo.bar[5].baz") to *names.  "prefix" will be attached to
   // the front of each name.
   static void FindInitializationErrors(const Message& message,
                                        const string& prefix,
-                                       std::vector<string>* errors);
+                                       vector<string>* errors);
 
  private:
   // All methods are static.  No need to construct.
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(ReflectionOps);
 };
 
 }  // namespace internal
 }  // namespace protobuf
 
 }  // namespace google
 #endif  // GOOGLE_PROTOBUF_REFLECTION_OPS_H__