Cherry pick https://github.com/etcd-io/etcd/pull/13932 to 3.4.
When etcdserver receives a LeaseRenew request, it may be still in
progress of processing the LeaseGrantRequest on exact the same
leaseID. Accordingly it may return a TTL=0 to client due to the
leaseID not found error. So the leader should wait for the appliedID
to be available before processing client requests.
Signed-off-by: Benjamin Wang <wachao@vmware.com>