Description:
------------
When i regist my own stream class, and use flock($h, LOCK_UN).
then steam_lock caled with undefined mode(0x8).

php-5.2.6/ext/standard/file.c
----
321 static int flock_values[] = { LOCK_SH, LOCK_EX, LOCK_UN };
snip...
348 act = flock_values[act - 1] | (operation & 4 ? LOCK_NB : 0);
349 if (php_stream_lock(stream, act)) {


Reproduce code:
---------------
<?php
class StreamTest
{
    function stream_open($path, $mode, $options, &$opened_path) {
		return true;
	}
    function stream_close() {
		return ;
	}
    function stream_lock($mode) {       
		printf( "0x%x\n", $mode ) ;
        return ;
    }
}
stream_register_wrapper("streamtest", "StreamTest");
$handle = fopen( 'streamtest://test', "r" ) ;
flock( $handle, LOCK_EX ) ;
flock( $handle, LOCK_UN ) ;
fclose($handle) ;


Expected result:
----------------
0x2
0x3


Actual result:
--------------
0x2
0x8