The old leader demotes lessor and all the leases' expire time will be
updated. Instead of returning incorrect remaining TTL, we should return
errors to force client retry.
Signed-off-by: Wei Fu <fuweid89@gmail.com>
This contains a slight refactoring to expose enough information
to write meaningful tests for auth applier v3.
Signed-off-by: Thomas Jungblut <tjungblu@redhat.com>