Fix of really fix UNKNOWN-CTE handling

Bartlomiej Nogas

2014-10-24 a235f79df9b3e94e52e22008e9af858e094fd25f

 program/lib/Roundcube/html.php

@@ -153,7 +153,7 @@
            $attr = array('src' => $attr);
        }
        return self::tag('img', $attr + array('alt' => ''), null, array_merge(self::$common_attrib,
            array('src','alt','width','height','border','usemap','onclick')));
            array('src','alt','width','height','border','usemap','onclick','onerror')));
    }

    /**