[BUGFIX] Handle response in NodeIndexing flushing correctly

Incorrect escaping of the newline character used in the flush method
in the NodeIndexing, resulting in incorrect log data if multiple
response lines were returned.

Author: mocdk-dev

Classes/Flowpack/ElasticSearch/ContentRepositoryAdaptor/Indexer/NodeIndexer.php

@@ -368,7 +368,7 @@ public function flush() {
 
 		if ($content !== '') {
 			$responseAsLines = $this->getIndex()->request('POST', '/_bulk', array(), $content)->getOriginalResponse()->getContent();
-			foreach (explode('\n', $responseAsLines) as $responseLine) {
+			foreach (explode("\n", $responseAsLines) as $responseLine) {
 				$response = json_decode($responseLine);
 				if (!is_object($response) || (isset($response->errors) && $response->errors !== FALSE)) {
 					$this->logger->log('Indexing Error: ' . $responseLine, LOG_ERR);