net/sched: cls_flower: Remove old entries from rhashtable

When replacing a rule we add the new rule to the rhashtable
but only remove the old if not in skip_sw.
This commit fix this and remove the old rule anyway.

Fixes: 35cc3cef ("net/sched: cls_flower: Reject duplicated rules also under skip_sw")
Signed-off-by: Roi Dayan <roid@mellanox.com>
Reviewed-by: Vlad Buslov <vladbu@mellanox.com>
Acked-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>