Reservation::isRenewDue() always returns true after service startup

The Reservation::isRenewDue() returns true for all reservations after service has been started, and the reservation has not been used. This causes potentially unacceptable behavior for licenses which declare their renewal policy as 'passive'.

When a client application first uses a cached reservation after service startup, the license service will check if the reservation requires renewal, but now this check will always succeed. This means a 'passive' reservation would be renewed before the actual renewal time.