Added test if self.model_filter is None

self.model_filter will be None if no list was ever loaded in the
Client, so listview.create_column_state would fail.

deluge/ui/gtkui/listview.py

@@ -307,6 +307,7 @@ class ListView:
                     position = index
                     break
         sort = None
+        if self.model_filter:
             sort_id, order = self.model_filter.get_sort_column_id()
             if self.get_column_name(sort_id) == column.get_title():
                 sort = sort_id