third_party/protobuf: Update to HEAD (f52e188fe4)

third_party/protobuf/csharp/src/AddressBook/Program.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 75 matching lines @@
                 catch (Exception e)
                 {
                     Console.WriteLine("Exception executing action: {0}", e);
                 }
                 Console.WriteLine();
             }
             return 0;
         }
     }
 }