Remove reference to non-existing option 'default_folders'

program/lib/Roundcube/rcube_config.php

@@ -39,7 +39,6 @@ class rcube_config
      */
     private $legacy_props = array(
         // new name => old name
-        'default_folders'      => 'default_imap_folders',
         'mail_pagesize'        => 'pagesize',
         'addressbook_pagesize' => 'pagesize',
         'reply_mode'           => 'top_posting',
@@ -143,10 +142,6 @@ class rcube_config
         foreach (array('drafts_mbox', 'junk_mbox', 'sent_mbox', 'trash_mbox') as $folder)
             $this->prop[$folder] = rcube_charset::convert($this->prop[$folder], RCUBE_CHARSET, 'UTF7-IMAP');
 
-        if (!empty($this->prop['default_folders']))
-            foreach ($this->prop['default_folders'] as $n => $folder)
-                $this->prop['default_folders'][$n] = rcube_charset::convert($folder, RCUBE_CHARSET, 'UTF7-IMAP');
-
         // set PHP error logging according to config
         if ($this->prop['debug_level'] & 1) {
             ini_set('log_errors', 1);