keybase_service_base: only run sessionLoggedIn for new sessions
keybase_service_base: only run sessionLoggedIn for new sessions

Issue: KBFS-2315

keybase/client,keybase/client,keybase/kbfs,keybase/client,keybase/kbfs,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/kbfs,keybase/client,keybase/client,keybase/kbfs,keybase/client,keybase/client