Update //third_party/protobuf to version 3.

third_party/protobuf/src/google/protobuf/unittest_preserve_unknown_enum2.proto

Index: third_party/protobuf/src/google/protobuf/unittest_preserve_unknown_enum2.proto
diff --git a/third_party/protobuf/src/google/protobuf/unittest_no_generic_services.proto b/third_party/protobuf/src/google/protobuf/unittest_preserve_unknown_enum2.proto
similarity index 78%
copy from third_party/protobuf/src/google/protobuf/unittest_no_generic_services.proto
copy to third_party/protobuf/src/google/protobuf/unittest_preserve_unknown_enum2.proto
index cffb4122c5c4f9d2e63a09d70c3784614617d88d..adf42968aaa53fcfa6db549b11b58f0d3238109b 100644
--- a/third_party/protobuf/src/google/protobuf/unittest_no_generic_services.proto
+++ b/third_party/protobuf/src/google/protobuf/unittest_preserve_unknown_enum2.proto
@@ -1,6 +1,6 @@
 // Protocol Buffers - Google's data interchange format
 // Copyright 2008 Google Inc.  All rights reserved.
-// http://code.google.com/p/protobuf/
+// 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
@@ -28,25 +28,23 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-// Author: kenton@google.com (Kenton Varda)
+syntax = "proto2";
 
-package google.protobuf.no_generic_services_test;
+package proto2_preserve_unknown_enum_unittest;
 
-// *_generic_services are false by default.
-
-message TestMessage {
-  optional int32 a = 1;
-  extensions 1000 to max;
-}
-
-enum TestEnum {
-  FOO = 1;
-}
-
-extend TestMessage {
-  optional int32 test_extension = 1000;
+enum MyEnum {
+  FOO = 0;
+  BAR = 1;
+  BAZ = 2;
 }
 
-service TestService {
-  rpc Foo(TestMessage) returns(TestMessage);
+message MyMessage {
+  optional MyEnum e = 1;
+  repeated MyEnum repeated_e = 2;
+  repeated MyEnum repeated_packed_e = 3 [packed=true];
+  repeated MyEnum repeated_packed_unexpected_e = 4;  // not packed
+  oneof o {
+    MyEnum oneof_e_1 = 5;
+    MyEnum oneof_e_2 = 6;
+  }
 }