TreeSelect树选择 组件，多选情况下，子节点选择后禁用，仍可在input中通过关闭，将选择后禁用的节点删除选中

[Jasonpetrelli]

• I have searched the issues of this repository and believe that this is not a duplicate.

Reproduction link

Steps to reproduce

• treeData数据中将选中的目标节点禁用（通过treeData和TreeNode生成的树都有此问题）
• 打开树里面的Node 2节点，可以看到生成的Child Node3是选中禁用状态
• 直接在input中点击Child Node3标签的删除x按钮，树中之前选中的Child Node3节点状态直接设置为了未选择

What is expected?

按照正常逻辑，选择并且禁用后的节点，不应该被input中的标签操作

What is actually happening?

选择并且禁用的节点，在树里面是不可操作情况，但可以通过标签的删除越过禁用，然后清除了数据

Environment	Info
antd	3.16.3
React	react
System	mac 10.14.4
Browser	chrome 73.0.3683.103

[Cuiyansong]

Two Missing Case:

1. Should not delete disabled selected node when click clear all button in input selector.
2. Should not delete disabled selected node when enter "Delete" key in input selector.
   Need discussion.