Use parse_rtattr_nested

(Logical change 1.129)
diff --git a/tc/q_htb.c b/tc/q_htb.c
index abc4971..828d4b1 100644
--- a/tc/q_htb.c
+++ b/tc/q_htb.c
@@ -246,8 +246,7 @@
 	if (opt == NULL)
 		return 0;
 
-	memset(tb, 0, sizeof(tb));
-	parse_rtattr(tb, TCA_HTB_RTAB, RTA_DATA(opt), RTA_PAYLOAD(opt));
+	parse_rtattr_nested(tb, TCA_HTB_RTAB, opt);
 
 	if (tb[TCA_HTB_PARMS]) {