message: Make sure random Config is valid.
diff: @@ -105,10 +105,10 @@ impl CoreConfig {
  let minimum_block_time = TimeDiff::from(rng.gen_range(1_000..60_000));
  let validator_slots = rng.gen_range(1..10_000);
  let finality_threshold_fraction = Ratio::new(rng.gen_range(1..100), 100);
  - let auction_delay = rng.gen::<u32>() as u64;
  + let auction_delay = rng.gen_range(1..5) as u64;
  let locked_funds_period = TimeDiff::from(rng.gen_range(600_000..604_800_000));
  let vesting_schedule_period = TimeDiff::from(rng.gen_range(600_000..604_800_000));
  - let unbonding_delay = rng.gen_range(1..1_000_000_000);
  + let unbonding_delay = rng.gen_range((auction_delay + 1)..1_000_000_000);
  let round_seigniorage_rate = Ratio::new(
  rng.gen_range(1..1_000_000_000),
  rng.gen_range(1..1_000_000_000),
  