Reverts third_party/protobuf: Update to HEAD (f52e188fe4)

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

Index: third_party/protobuf/src/google/protobuf/reflection_ops.h
diff --git a/third_party/protobuf/src/google/protobuf/reflection_ops.h b/third_party/protobuf/src/google/protobuf/reflection_ops.h
index 45d8c650ef81580b85c8692091b64d50e1c52cbe..4775911e84a278c7cc416d3749640e2321b80319 100644
--- a/third_party/protobuf/src/google/protobuf/reflection_ops.h
+++ b/third_party/protobuf/src/google/protobuf/reflection_ops.h
@@ -67,7 +67,7 @@ class LIBPROTOBUF_EXPORT ReflectionOps {
   // 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.