response object doesn't set url or requestUrl if gzip encoding

[jrgm]

Tested with got@6.6.0

var got = require('got')
var url = 'http://google.com/'
var encoding = process.argv[2]
var requestOptions = {
  headers: {
    'accept-encoding': encoding
  }
}
got(url, requestOptions)
  .then((res) => {
    console.log('res.url', res.url, typeof res.url, res.requestUrl)
  })

Output:

$ node test.js identity
res.url http://www.google.com/ string http://google.com/

$ node test.js gzip
res.url undefined undefined undefined