Colab hotfix: forgot glob import (#952)

Created using Colaboratory

colab/demo.ipynb

@@ -7,7 +7,7 @@
         "colab_type": "text"
       },
       "source": [
-        "<a href=\"https://colab.research.google.com/github/nerfstudio-project/nerfstudio/blob/alex%2Fstreamline_colab/colab/demo.ipynb\" target=\"_parent\"><img src=\"https://colab.research.google.com/assets/colab-badge.svg\" alt=\"Open In Colab\"/></a>"
+        "<a href=\"https://colab.research.google.com/github/nerfstudio-project/nerfstudio/blob/alex%2Frecord3d_colab_hotfix/colab/demo.ipynb\" target=\"_parent\"><img src=\"https://colab.research.google.com/assets/colab-badge.svg\" alt=\"Open In Colab\"/></a>"
       ]
     },
     {
@@ -63,7 +63,7 @@
     },
     {
       "cell_type": "code",
-      "execution_count": 2,
+      "execution_count": null,
       "metadata": {
         "colab": {
           "base_uri": "https://localhost:8080/"
@@ -151,6 +151,7 @@
         "#@markdown <h1> Downloading and Processing Data</h1>\n",
         "#@markdown <h3>Pick the preset scene or upload your own images/video</h3>\n",
         "import os\n",
+        "import glob\n",
         "from google.colab import files\n",
         "from IPython.core.display import display, HTML\n",
         "\n",