Fixed bug which prevented a field query as described in the example:

```
$result = Article::find()->query(["field" => ["title" => "yii"]])->all();
````
Updated elasiticsearch changelog
Merge branch 'master' of github.com:mintao/yii2 into mintao-master

Conflicts:
	extensions/yii/elasticsearch/CHANGELOG.md
updated elasticsearch querybuilder test to use yiitest index

better not delete all to avoid data loss

pr #2324