simplefs: make sure a TLF is initialized before changing sync config
simplefs: make sure a TLF is initialized before changing sync config

This is required now that we moved it into the FBO instance.

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