pbrd: Set next/prev to NULL on cached nexthops

When we copy a new nexthop to cache and track, set its
next and prev pointers to NULL. We don't want those since
this is to be treated as a single nexthop.Other nexthops that
aren't in a group could hash to this nexthop so it doesn't
make sense to keep those pointers in the cache.

Signed-off-by: Stephen Worley <sworley@cumulusnetworks.com>

pbrd/pbr_nht.c

@@ -66,6 +66,8 @@ static void *pbr_nhrc_hash_alloc(void *p)
 {
 	struct nhrc *nhrc = XCALLOC(MTYPE_PBR_NHG, sizeof(struct nhrc));
 	nhrc->nexthop = *(struct nexthop *)p;
+	nhrc->nexthop.next = NULL;
+	nhrc->nexthop.prev = NULL;
 	return nhrc;
 }