interfaces: fix ClearAllTlfBlocks comment
interfaces: fix ClearAllTlfBlocks comment

Suggested by songgao.

Issue: #1909

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