feedparser: fix normalize_encoding() not working properly for some encodings

classes/feedparser.php

@@ -18,7 +18,7 @@ class FeedParser {
 
 			$encoding = strtolower($matches[2]);
 
-			if (in_array($encoding, mb_list_encodings()))
+			if (in_array($encoding, array_map('strtolower', mb_list_encodings()))) {
 				$data = mb_convert_encoding($data, 'UTF-8', $encoding);
 
 			$data = preg_replace('/^<\?xml[\t\n\r ].*?\?>/s', $matches[1] . "UTF-8" . $matches[3] , $data);