message: Update snapshot_util.cc
diff: @@ -906,7 +906,7 @@ Status DetermineOpState(const std::string& mode_string, bool file_exists,
  return Status::OK();
  }
  - int64 expiration_timer = EnvTime::NowMicros()
  + int64 expiration_timer = static_cast<int64>(EnvTime::NowMicros())
  - pending_snapshot_expiry_seconds * 1000000;
  if (metadata->creation_timestamp() >= expiration_timer) {
  