Drive callback deletion through the public reinit transition

tests/test_etcp_init_liveness.c

@@ -259,7 +259,7 @@ static void delete_in_callback(unsigned keepalive) {
     uint64_t epoch = ep[1].conn->reset_id;
     link->recv_keepalive = 0;
     if (keepalive) etcp_link_send_keepalive(link);
-    else etcp_link_send_init(link, 0, 0);
+    else etcp_link_enter_reinit(link);
     link->recv_keepalive = 1;
     run_for(1000);
     CHECK(close_fired == 1 && ep[1].conn->links && !ep[1].conn->links->next && ep[1].conn->links_up == 1);