Clean up error message for raft lease request

If we don't have a client yet and is expected to process a raft lease
command, we want the error (now warning) message to be less cryptic.

Dropped to a warning, as operators should be aware of the message, but
don't need to jump onto the error message itself. This should resolve
itself once a client has been connected.

api/controller/raftlease/client.go

@@ -542,7 +542,7 @@ func (r *remote) SetAddress(addr string) {
 // Request performs a request against a specific api.
 func (r *remote) Request(ctx context.Context, command *raftlease.Command) error {
 	if r.client == nil {
-		r.config.Logger.Errorf("No attached client instance; dropping command: %v", command)
+		r.config.Logger.Warningf("not currently connected to the controller raft engine; dropping lease command: %v", command)
 		return lease.ErrDropped
 	}