Add a missing line to ASR_with_NeMo.ipynb (#3908)

Signed-off-by: J.P Lee <koreanfeel@gmail.com>

tutorials/asr/ASR_with_NeMo.ipynb

@@ -25,15 +25,6 @@
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
    "version": "3.7.7"
-  },
-  "pycharm": {
-   "stem_cell": {
-    "cell_type": "raw",
-    "source": [],
-    "metadata": {
-     "collapsed": false
-    }
-   }
   }
  },
  "cells": [
@@ -801,6 +792,7 @@
     "# Setup the test data loader and make sure the model is on GPU\n",
     "first_asr_model.setup_test_data(test_data_config=params['model']['validation_ds'])\n",
     "first_asr_model.cuda()\n",
+    "first_asr_model.eval()\n",
     "\n",
     "# We will be computing Word Error Rate (WER) metric between our hypothesis and predictions.\n",
     "# WER is computed as numerator/denominator.\n",
@@ -1173,4 +1165,4 @@
    "outputs": []
   }
  ]
-}
+}