cmd/puppeth: force tiny memory for geth attach in id lookup

cmd/puppeth/module_node.go

@@ -221,7 +221,7 @@ func checkNode(client *sshClient, network string, boot bool) (*nodeInfos, error)
 
 	// Container available, retrieve its node ID and its genesis json
 	var out []byte
-	if out, err = client.Run(fmt.Sprintf("docker exec %s_%s_1 geth --exec admin.nodeInfo.id attach", network, kind)); err != nil {
+	if out, err = client.Run(fmt.Sprintf("docker exec %s_%s_1 geth --exec admin.nodeInfo.id --cache=16 attach", network, kind)); err != nil {
 		return nil, ErrServiceUnreachable
 	}
 	id := bytes.Trim(bytes.TrimSpace(out), "\"")