Add the natdiscovery.pb.go file to the repository
Otherwise, while building downstream images we have issues
re-generating this file. It's simpler to commit the file
into the repository
@@ -13,4 +13,3 @@ scripts/broker-info.subm*
Dockerfile.dapper[0-9]*
.shflags
Makefile.dapper
-pkg/natdiscovery/proto/*.pb.go
