Less confusing log message

A non-primary address isn't necessarily secondary, that's an independent
flag.

nest/iface.c

@@ -142,7 +142,7 @@ ifa_send_notify(struct proto *p, unsigned c, struct ifa *a)
     {
       if (p->debug & D_IFACES)
 	log(L_TRACE "%s < %s address %I/%d on interface %s %s",
-	    p->name, (a->flags & IA_PRIMARY) ? "primary" : "secondary",
+	    p->name, (a->flags & IA_PRIMARY) ? "primary" : "non-primary",
 	    a->prefix, a->pxlen, a->iface->name,
 	    (c & IF_CHANGE_UP) ? "added" : "removed");
       p->ifa_notify(p, c, a);