Defer session startup until KAMD is up
Otherwise we can session restore occur before kwin has loaded activities. This means kwin will fail to put windows back on the correct activity. Races are avoided because ksmserver will then make a blocking DBus call to kwin on session restore. DBus guarantees order so it will have also dispatched the service status to kwin and we know kwin will have handle that first. CCBUG: 456873 Testing done: Added "sleep(10)" into the main function. Everything resumed on the correct activities.