Bug 1411450 - Add the protobuf version to LayerScopePacket.proto. r?mattwoodrow This is essentially a no-op but it does silence the following warning whenever the *.pb.* files are re-generated: [libprotobuf WARNING google/protobuf/compiler/parser.cc:546] No syntax specified for the proto file: LayerScopePacket.proto. Please use 'syntax = "proto2";' or 'syntax = "proto3";' to specify a syntax version. (Defaulted to proto2 syntax.) MozReview-Commit-ID: 6L1TXHLcjsj

--- a/gfx/layers/protobuf/LayerScopePacket.proto
+++ b/gfx/layers/protobuf/LayerScopePacket.proto
@@ -1,10 +1,12 @@
 /* vim:set ts=2 sw=2 sts=2 et: */
 
+syntax = "proto2";
+
 option optimize_for = LITE_RUNTIME;
 
 package mozilla.layers.layerscope;
 
 // ===============================
 // Server to Client messages
 // ===============================
 message FramePacket {