ovn-northd: Remove useless flow for GW_REDIRECT.

Remove the flow in lr_in_gw_redirect stage:

        A priority-150 logical flow with match
        <code>outport == <var>GW</var> &amp;&amp;
        eth.dst == 00:00:00:00:00:00</code> has actions
        <code>outport = <var>CR</var>; next;</code>, where
        <var>GW</var> is the logical router distributed gateway
        port and <var>CR</var> is the <code>chassisredirect</code>
        port representing the instance of the logical router
        distributed gateway port on the
        <code>redirect-chassis</code>.

The commit c0bf32d ("Manage ARP process locally in a DVR scenario") updated
the priority-100 flow in this stage to priority 200, which makes this
priority-150 flow useless, because whatever packets matching this flow
would also match the priority-50 flow.

Cc: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Tested-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Acked-by: Numan Siddique <numans@ovn.org>
Signed-off-by: Han Zhou <hzhou@ovn.org>

northd/ovn-northd.8.xml

@@ -2908,18 +2908,6 @@ icmp4 {
     </p>
 
     <ul>
-      <li>
-        A priority-150 logical flow with match
-        <code>outport == <var>GW</var> &amp;&amp;
-        eth.dst == 00:00:00:00:00:00</code> has actions
-        <code>outport = <var>CR</var>; next;</code>, where
-        <var>GW</var> is the logical router distributed gateway
-        port and <var>CR</var> is the <code>chassisredirect</code>
-        port representing the instance of the logical router
-        distributed gateway port on the
-        <code>redirect-chassis</code>.
-      </li>
-
       <li>
         For each NAT rule in the OVN Northbound database that can
         be handled in a distributed manner, a priority-200 logical

northd/ovn-northd.c

@@ -10172,17 +10172,6 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports,
             ovn_lflow_add_with_hint(lflows, od, S_ROUTER_IN_GW_REDIRECT, 50,
                                     ds_cstr(&match), ds_cstr(&actions),
                                     stage_hint);
-
-            /* If the Ethernet destination has not been resolved,
-             * redirect to the central instance of the l3dgw_port.
-             * Such traffic will be replaced by an ARP request or ND
-             * Neighbor Solicitation in the ARP request ingress
-             * table, before being redirected to the central instance.
-             */
-            ds_put_format(&match, " && eth.dst == 00:00:00:00:00:00");
-            ovn_lflow_add_with_hint(lflows, od, S_ROUTER_IN_GW_REDIRECT, 150,
-                                    ds_cstr(&match), ds_cstr(&actions),
-                                    stage_hint);
         }
 
         /* Packets are allowed by default. */