clickoutside unbind is incorrect if there is multiple clickoutsides

[meowtec]

ElementUI version

1.0.0-rc.2

OS/Browers version

macOS/Chrome 53

Vue version

2.0.0-rc.6

Reproduction Link

null

Steps to reproduce

<div class="div1" v-if="show" v-clickoutside="out1"></div>
<div class="div2" v-if="show" v-clickoutside="out2"></div>

execute:

show = false
sleep 100
show = true
sleep 100
show = false
sleep 100
show = true
...

Now click outside div1 and div2

What is Expected?

out1 and out2 will execute only once.

What is actually happening?

out1 and out2 execute many times.

---

https://github.com/ElemeFE/element/blob/master/src/utils/clickoutside.js

用一个全局的变量 handler 存储 addEventListener 是有问题的。

在 Vue1 中，可以通过 this 访问 Directive 对象，而 Vue2 不行，目前能想到的处理方法是把实例数据挂到当前节点上。

[QingWei-Li]

确实是，忽略这问题了