Description:
------------
Prepared statements with ? doesn't work with the OCI driver.


Reproduce code:
---------------
<?php
$DB = new pdo("oci:dbname=DATABASE", "user", "password");
$stmt = $DB->prepare('INSERT INTO test VALUES(?, ?, ?)');
$stmt->execute(array("1", "2", "3"));
var_dump($stmt->errorInfo());
?>

Actual result:
--------------
array(3) {
  [0]=>
  string(5) "HY000"
  [1]=>
  int(1036)
  [2]=>
  string(108) "OCIBindByPos: ORA-01036: illegal variable name/number
 (/mnt/data5/PHP/head/ext/pdo_oci/oci_statement.c:260)"
}