Merge pull request #1 from dukefsc/match_all_query_fix_patch

Fix match_all query to be compliant with ER 5.4

Author: babenkoivan

src/ElasticEngine.php

@@ -262,7 +262,7 @@ protected function performSearch(Builder $builder, array $options = []) {
         } else {
             $payload = $this->buildSearchQueryPayload(
                 $builder,
-                ['must' => ['match_all' => []]],
+                ['must' => ['match_all' => new \stdClass()]],
                 $options
             );
 
@@ -323,4 +323,4 @@ public function getTotalCount($results)
     {
         return $results['hits']['total'];
     }
-}
+}