Honor remember_login_cookie_lifetime

If the remember_login_cookie_lifetime is set to 0 this means we do not
want to use remember me at all. In that case we should also not creatae
a remember me cookie and should create a proper temp token.

Further this specifies that is not 0 the remember me time should always
be larger than the session timeout. Because else the behavior is not
really defined.

Signed-off-by: Roeland Jago Douma <roeland@famdouma.nl>