Merge remote-tracking branch 'remotes/origin/5.2' into 6.0-dev

# Conflicts:
#	EventListener/TerminateListener.php
#	composer.json

Author: saimaz

Service/ExportService.php

@@ -66,7 +66,6 @@ public function exportIndex(
         $filename = str_replace('.json', '', $filename);
         $writer = $this->getWriter($this->getFilePath($filename.'.json'), $metadata['count']);
 
-        $file = [];
         foreach ($results as $data) {
             if ($counter >= $maxLinesInFile) {
                 $writer->finalize();
@@ -83,7 +82,6 @@ public function exportIndex(
 
             $doc = array_intersect_key($data, array_flip(['_id', '_type', '_source']));
             $writer->push($doc);
-            $file[] = $doc;
             $progress->advance();
             $counter++;
         }