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

third_party/protobuf/js/commonjs/test6/test6.proto

Index: third_party/protobuf/js/commonjs/test6/test6.proto
diff --git a/third_party/protobuf/js/test4.proto b/third_party/protobuf/js/commonjs/test6/test6.proto
similarity index 89%
copy from third_party/protobuf/js/test4.proto
copy to third_party/protobuf/js/commonjs/test6/test6.proto
index cf2451e9cbe483e1b06efd227f29f17e655077ce..a060925f2d505d384dbd1387aec418eb3e66c23c 100644
--- a/third_party/protobuf/js/test4.proto
+++ b/third_party/protobuf/js/commonjs/test6/test6.proto
@@ -1,5 +1,5 @@
 // Protocol Buffers - Google's data interchange format
-// Copyright 2008 Google Inc.  All rights reserved.
+// Copyright 2016 Google Inc.  All rights reserved.
 // https://developers.google.com/protocol-buffers/
 //
 // Redistribution and use in source and binary forms, with or without
@@ -28,15 +28,13 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-syntax = "proto2";
+syntax = "proto3";
 
 option java_package = "com.google.apps.jspb.proto";
 option java_multiple_files = true;
 
-package jspb.exttest;
+package jspb.test.importing;
 
-import "test3.proto";
-
-extend TestExtensionsMessage {
-  optional ExtensionMessage floating_msg_field_two = 103;
+message ImportedMessage {
+  string string_value = 1;
 }