Merge pull request #2641 from Carreau/thisthat

undefinied that -> this

IPython/frontend/html/notebook/static/js/notebook.js

@@ -1100,7 +1100,7 b' var IPython = (function (IPython) {'
 
     Notebook.prototype.execute_cells_below = function () {
         this.execute_cell_range(this.get_selected_index(), this.ncells());
-        that.scroll_to_bottom();
+        this.scroll_to_bottom();
     };
 
     Notebook.prototype.execute_cells_above = function () {