Update third_party/protobuf to protobuf-v3.0.0-beta-3

third_party/protobuf/csharp/src/Google.Protobuf.Test/TestCornerCases.cs

 #region Copyright notice and license
 // 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
@@ skipping 25 matching lines @@
 namespace Google.Protobuf
 {
     public class TestCornerCases
     {
         [Test]
         public void TestRoundTripNegativeEnums()
         {
             NegativeEnumMessage msg = new NegativeEnumMessage
             {
                 Value = NegativeEnum.MinusOne,
-                Values = { NegativeEnum.NEGATIVE_ENUM_ZERO, NegativeEnum.MinusOne, NegativeEnum.FiveBelow },
-                PackedValues = { NegativeEnum.NEGATIVE_ENUM_ZERO, NegativeEnum.MinusOne, NegativeEnum.FiveBelow }
+                Values = { NegativeEnum.Zero, NegativeEnum.MinusOne, NegativeEnum.FiveBelow },
+                PackedValues = { NegativeEnum.Zero, NegativeEnum.MinusOne, NegativeEnum.FiveBelow }
             };
 
             Assert.AreEqual(58, msg.CalculateSize());
 
             byte[] bytes = new byte[58];
             CodedOutputStream output = new CodedOutputStream(bytes);
 
             msg.WriteTo(output);
             Assert.AreEqual(0, output.SpaceLeft);
 
             NegativeEnumMessage copy = NegativeEnumMessage.Parser.ParseFrom(bytes);
             Assert.AreEqual(msg, copy);
         }
     }
 }