Adapt control metrics fixture to per-link ACK ownership

tests/test_control_server.c

@@ -183,7 +183,7 @@ static void test_metrics(void) {
     struct control_client* client = fixture_accept(&f); assert(client);
     struct ll_queue empty = {0};
     struct ETCP_CONN conn = {.peer_node_id = 42, .input_queue = &empty, .input_send_q = &empty,
-        .input_wait_ack = &empty, .ack_q = &empty, .recv_q = &empty, .output_queue = &empty};
+        .input_wait_ack = &empty, .recv_q = &empty, .output_queue = &empty};
     struct ETCP_LINK links[2] = {{.local_link_id = 7}, {.local_link_id = 8}};
     links[0].next = &links[1]; conn.links = links;
     f.inst.connections = queue_new(f.inst.ua, 16, 0, 8, "test connections"); assert(f.inst.connections);