update train.py

Not using bucketing if continue training from checkpoint_per_batch in 1st epoch

train.py

@@ -194,7 +194,7 @@ def main():
  }
  for tag, val in info.items():
  logger.scalar_summary(tag, val, i + 1)
- if not args.no_bucketing:
+ if not args.no_bucketing and epoch != 0:
  print("Using bucketing sampler for the following epochs")
  train_dataset = SpectrogramDatasetWithLength(audio_conf=audio_conf, manifest_filepath=args.train_manifest,
  labels=labels,