Ability to not pass implicit headers "application/x-protobuf" to the request

[abhivaikar]

One of the apis (that requires protobuf encoded payload over http) I'm testing accepts content-type as ONLY binary/octet-stream.

Hence I'm passing the header from protoman like this:

But when I make the request, the service is receiving content-type as binary/octet-stream,application/x-protobuf. I guess that means Protoman is attaching application/x-protobuf in the header. Due to this, the api call fails.

Can this implicit passing of application/x-protobuf be removed or made optional?