Issue title: Zlib InflateRaw null reference
 Issue body: - **Version**: v5.10.0 (also seen on 4.3.0)
- **Platform**: Darwin Kernel Version 14.5.0
- **Subsystem**: zlib

Zlib references a null object on close after an error:

``` js
var zlib = require('zlib');
var inflate = zlib.createInflateRaw(15);
inflate.on('error', function(e) {  });
inflate.write('something invalid');
setTimeout(function(){
    inflate.close();  
}, 100);
```

Output:

```
$ node inflate-close.js 
zlib.js:465
  this._handle.close();
              ^

TypeError: Cannot read property 'close' of null
    at InflateRaw.Zlib.close (zlib.js:465:15)
    at null._onTimeout (/tmp/inflate-close.js:8:13)
    at Timer.listOnTimeout (timers.js:92:15)
```

See websockets/ws#664

 Comments: 
 Comment 0: Looks like it's already being fixed: https://github.com/nodejs/node/pull/5982
{'source': 'GithubIssues', 'repo_name_with_owner': 'nodejs/node', 'issue_id': 145623242, 'repo_stars': 91315.0}