Remove obsolete commented code

Author: BHFock

ngux/module_3/NGUX_Module-3_exercise-2_rose-stem_viewer.ipynb

@@ -135,7 +135,6 @@
     "face_lat = data['Mesh2d_face_y'][:]\n",
     "gv_mesh = gv.Transform.from_unstructured(face_lon, face_lat, connectivity=face_conn, data=field_2d)\n",
     "\n",
-    "#pv.start_xvfb()\n",
     "plotter = gv.GeoPlotter()\n",
     "plotter.add_mesh(gv_mesh, cmap=\"nipy_spectral\", show_edges=True)\n",
     "plotter.add_coastlines(color='k')\n",