Heya

I'm getting errors like this in production - my code is loading pages from wild http servers, so this is most likely related to them being buggy.

```
{ [Error: unexpected end of file] errno: -5, code: 'Z_BUF_ERROR' }
Error: unexpected end of file
    at Zlib._handle.onerror (zlib.js:363:17)
```

This is on node 4x and v5.7.0

Would it be possible to add a `stream.on('error'` clause in axios\lib\adapters\http.js and throw this as an exception to the axios response promise?

lib/adapters/http.js
case 'gzip':
    case 'compress':
    case 'deflate':
      
      stream = stream.pipe(zlib.createUnzip());
      
      delete res.headers['content-encoding'];
      break;
    }
    var responseBuffer = [];
    stream.on('data', function handleStreamData(chunk) {
      responseBuffer.push(chunk);
      
      if (config.maxContentLength > -1 && Buffer.concat(responseBuffer).length > config.maxContentLength) {
        reject(new Error('maxContentLength size of ' + config.maxContentLength + ' exceeded'));
      }
    });
    stream.on('end', function handleStreamEnd() {
      var d = Buffer.concat(responseBuffer);
      if (config.responseType !== 'arraybuffer') {
        d = d.toString('utf8');
      }
      var response = {
        data: transformData(
          d,
          res.headers,
          config.transformResponse
        ),
        status: res.statusCode,
        statusText: res.statusMessage,