don't crash on invalid cell parameter passed to goto cell

combo_plugin_gnm/templatetags/gnm.py

@@ -730,7 +730,7 @@ def json_script(value, element_id):
 def get_goto_cell(page, request):
     try:
         cell = ConfigJsonCell.objects.get(id=request.GET['to'])
-    except (ConfigJsonCell.DoesNotExist, KeyError):
+    except (ConfigJsonCell.DoesNotExist, ValueError, KeyError):
         return None
     if cell.page.template_name != 'place':
         return cell