third_party/protobuf: Update to HEAD (83d681ee2c)

third_party/protobuf/src/google/protobuf/empty.proto

 // 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 19 matching lines @@
 
 syntax = "proto3";
 
 package google.protobuf;
 
 option csharp_namespace = "Google.Protobuf.WellKnownTypes";
 option go_package = "github.com/golang/protobuf/ptypes/empty";
 option java_package = "com.google.protobuf";
 option java_outer_classname = "EmptyProto";
 option java_multiple_files = true;
-option java_generate_equals_and_hash = true;
 option objc_class_prefix = "GPB";
 option cc_enable_arenas = true;
 
 // A generic empty message that you can re-use to avoid defining duplicated
 // empty messages in your APIs. A typical example is to use it as the request
 // or the response type of an API method. For instance:
 //
 //     service Foo {
 //       rpc Bar(google.protobuf.Empty) returns (google.protobuf.Empty);
 //     }
 //
 // The JSON representation for `Empty` is empty JSON object `{}`.
 message Empty {}