Description:
------------
OpenSSL* doesnt support streamwrappers

Reproduce code:
---------------
<?php

class StringWrapper {

    public function __call($method, $args) {
        var_dump($method);
        die();
    }

}
stream_wrapper_register('string', 'StringWrapper');
openssl_pkcs7_sign('string://input', 'string://output', 'file://foo.pem',  array("file://bar.pem", ""), array());

?>


Expected result:
----------------
string(11) "stream_open"

Actual result:
--------------
Warning: openssl_pkcs7_sign(): error opening input file string://input! 
in cert.php on line 12