Changes password for user with username. Parameters old_password and new_password should indicate old and new passwords respectively.
如果成功则返回 TRUE，失败则返回 FALSE。
注: In PHP versions before 5.0.0 you must use ocipasswordchange() instead. This name still can be used, it was left as alias of oci_password_change() for downwards compatability. This, however, is deprecated and not recommended.