[FIX] web_kanban: quick redrag of kanban records

When dropping a record, it is updated and rerendered. The problem with
this behaviour is that if the record is redrag immediately after drop,
jquery-ui throws an error as the widget the user is trying to re-move
is being rerendered.

The solution provided by this commit is to block the draggable feature
while the record is being rerendered.

addons/web_kanban/static/src/js/kanban_column.js

@@ -91,7 +91,7 @@ var KanbanColumn = Widget.extend({
                 connectWith: '.o_kanban_group',
                 revert: 0,
                 delay: 0,
-                items: '> .o_kanban_record',
+                items: '> .o_kanban_record:not(.o_updating)',
                 helper: 'clone',
                 cursor: 'move',
                 over: function () {
@@ -117,6 +117,7 @@ var KanbanColumn = Widget.extend({
                         // adding record to this column
                         self.records.push(record);
                         record.setParent(self);
+                        ui.item.addClass('o_updating');
                         self.trigger_up('kanban_column_add_record', {record: record});
                     }
                     self.update_column();