fixes transposed from-charset and to-charset arguments in

mbstring_convert_encodng

Author: mbunzel

lib/classes/Swift/Mime/MimePart.php

@@ -203,7 +203,7 @@ protected function _convertString($string)
         if (!in_array($charset, array('utf-8', 'iso-8859-1', ''))) {
             // mb_convert_encoding must be the first one to check, since iconv cannot convert some words.
             if (function_exists('mb_convert_encoding')) {
-                $string = mb_convert_encoding($string, $charset, 'utf-8');
+                $string = mb_convert_encoding($string, 'utf-8', $charset);
             } elseif (function_exists('iconv')) {
                 $string = iconv($charset, 'utf-8//TRANSLIT//IGNORE', $string);
             } else {