incorrect initialization

Fix initialization in libnetlink.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
diff --git a/lib/libnetlink.c b/lib/libnetlink.c
index 5c6a4dc..555dd5c 100644
--- a/lib/libnetlink.c
+++ b/lib/libnetlink.c
@@ -40,7 +40,7 @@
 	int sndbuf = 32768;
 	int rcvbuf = 32768;
 
-	memset(rth, 0, sizeof(rth));
+	memset(rth, 0, sizeof(*rth));
 
 	rth->fd = socket(AF_NETLINK, SOCK_RAW, protocol);
 	if (rth->fd < 0) {