correcting training file name

Author: Talia Chopra

training/distributed_training/pytorch/model_parallel/bert/smp_bert_tutorial.ipynb

@@ -228,7 +228,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "pytorch_estimator = PyTorch(\"sagemaker_rbk_pretrain.py\",\n",
+    "pytorch_estimator = PyTorch(\"sagemaker_smp_pretrain.py\",\n",
     "                            role=role,\n",
     "                            instance_type=\"ml.p3.16xlarge\",\n",
     "                            volume_size=200,\n",