hasOpcRequestId simplification

[AaronDabney]

function hasOpcRequestId(headers: Headers) {
  if (headers.has(OPC_REQUEST_ID_HEADER)) {
    return true;
  }
  return false;
}

can be simplified

function hasOpcRequestId(headers: Headers) {
    return headers.has(OPC_REQUEST_ID_HEADER)
}

PR to follow