prevent console.log( http://0.0.0.0:4000 )

I update hexo from v2.5.7 to v2.8.3

my _config.yml file was create by `hexo init .` hexo@2.5.7
```yaml
port: 4000
server_ip: 0.0.0.0
```

then I run `hexo serve` , message shows like
`[info] Hexo is running at http://0.0.0.0:4000/. Press Ctrl+C to stop.`

in assets/_config.yml
```yaml
server_ip: 0.0.0.0  #before v2.8.2
server_ip: localhost #v2.8.2 & after
```

And this url (http://0.0.0.0) is not accessable ...