Fix finetuning tasks after T5 pipeline merge.

tasks/finetune_utils.py

@@ -25,6 +25,7 @@ from megatron import get_timers
 from megatron import mpu
 from megatron.checkpointing import load_checkpoint
 from megatron.checkpointing import save_checkpoint
+from megatron.model import ModelType
 from megatron.training import evaluate_and_print_results
 from megatron.training import setup_model_and_optimizer
 from megatron.training import train_step
@@ -248,6 +249,7 @@ def _train(model, optimizer, lr_scheduler, forward_step,
 
 
 def finetune(train_valid_datasets_provider, model_provider,
+             model_type=ModelType.encoder_or_decoder,
              forward_step=_cross_entropy_forward_step,
              end_of_epoch_callback_provider=None,
              task_collate_fn=None):
@@ -277,7 +279,7 @@ def finetune(train_valid_datasets_provider, model_provider,
 
     # Build model, optimizer and learning rate scheduler.
     timers('model and optimizer').start()
-    model, optimizer, lr_scheduler = setup_model_and_optimizer(model_provider)
+    model, optimizer, lr_scheduler = setup_model_and_optimizer(model_provider, model_type)
     timers('model and optimizer').stop()
 
     # If pretrained checkpoint is provided and we have not trained for