message: Remove log info about reference edge placement unless user requests
  logging of device placement.
  Can spam logs when user
  can do nothing about it due to usage of device functions in higher-level
  library code.
diff: @@ -690,17 +690,20 @@ Status SimplePlacer::Run() {
  const auto& dest_parsed_name = dst_root.device_name;
  if (DeviceNameUtils::HasSomeDetails(source_parsed_name) &&
  DeviceNameUtils::HasSomeDetails(dest_parsed_name)) {
  - // Add a log saying that we are ignoring a specified device
  - // for 'dst' if the two names were incompatible.
  + // Ignore a specified device for 'dst' if the two names were
  + // incompatible.
  if (!DeviceNameUtils::AreCompatibleDevNames(source_parsed_name,
  dest_parsed_name)) {
  + if (log_device_placement_) {
  LOG(INFO) << "Ignoring device specification "
  << DeviceNameUtils::ParsedNameToString(dest_parsed_name)
  << " for node '" << dst->name()
  << "' because the input edge from '" << src->name()
  << "' is a reference connection and already has a device "
  "field set to "
  - << DeviceNameUtils::ParsedNameToString(source_parsed_name);
  + << DeviceNameUtils::ParsedNameToString(
  + source_parsed_name);
  + }
  // Make 'dst' colocated with the source
  dst_root.device_name = source_parsed_name;
  