fix local mode instance type edge case

Author: ajaykarpur

sagemaker-python-sdk/pytorch_cnn_cifar10/pytorch_local_mode_cifar10.ipynb

@@ -67,12 +67,14 @@
     "import os\n",
     "import subprocess\n",
     "\n",
+    "instance_type = \"local\"\n",
+    "\n",
     "try:\n",
     "    if subprocess.call(\"nvidia-smi\") == 0:\n",
     "        ## Set type to GPU if one is present\n",
     "        instance_type = \"local_gpu\"\n",
     "except:\n",
-    "    instance_type = \"local\"\n",
+    "    pass\n",
     "\n",
     "print(\"Instance type = \" + instance_type)"
    ]