message: Log the error status for failed CUDA EnablePeerAccess.
  This would help debug issues like this:
diff: @@ -949,7 +949,7 @@ Status EnablePeerAccess(gpu::Platform* platform,
  if (!status.ok()) {
  LOG(WARNING)
  << "Unable to enable peer access between device ordinals "
  - << i_gpu_id << " and " << j_gpu_id;
  + << i_gpu_id << " and " << j_gpu_id << ", status: " << status;
  } else {
  ++enabled_peer_count;
  }
  