Remove the Update method from the Keybase interface.
Remove redundant lazy keybase implementation altogether.
Created LegacyKeybase interface to restrict capabilities to
only those required by keys commands that deal with
legacy keybase such as update and migrate.
Rename keyring.New() -> keyring.NewLegacy().
Rename client/keys.NewKeyBaseFromDir -> NewLegacyKeyBaseFromDir.
crypto/keyiring.NewInMemory() now returns a in-memory keyring.
BackendMemory is added yet not exposed via command line
--keyring-backend flag. keys add uses it when --dry-run flag
is on.
2a7a408d35