Description:
------------
Binary data saved in cache not reading from cache by nginx


Reproduce code:
---------------
$memDB = new Memcached();
$memDB->addServer('localhost',11211,50);
$fp = fopen('png.png','r');
$data = fread($fp, filesize('png.png'));
$memDB->set('/test',$data);

nginx conf
location / {
    #all non static request in index.php. wdevil
    add_header    Content-Type  "image/png;";
    set             $memcached_key   "/test";
    memcached_pass  localhost:11211;
}

nginx response to browser binary data. no png binary.
If i replace Memcached --> Memcache class. All ok.

Expected result:
----------------
png img in browser