Description:
------------
Calling stream_filter_remove() closes the stream when the filter is a user filter.

Reproduce code:
---------------
class user_filter extends php_user_filter {
        function filter($in, $out, &$consumed, $closing) {
                while($bucket = stream_bucket_make_writeable($in)) {
                        $consumed += $bucket->datalen;
                        stream_bucket_append($out, $bucket);
                }
                return PSFS_PASS_ON;
        }
}
stream_filter_register('user_filter','user_filter');

$fd = fopen('/tmp/test','w');
$filter = stream_filter_append($fd, 'user_filter');
stream_filter_remove($filter);
var_dump(fclose($fd));

Expected result:
----------------
bool(true)

Actual result:
--------------
Warning: fclose(): 5 is not a valid stream resource in /tmp/rep.php on line 15
bool(false)