Modules compatibility: down flag in ngx_peer_connection_t.

src/event/ngx_event_connect.h

diff --git a/src/event/ngx_event_connect.h b/src/event/ngx_event_connect.h
index 7253ebb..d3b2378 100644
--- a/src/event/ngx_event_connect.h
+++ b/src/event/ngx_event_connect.h
@@ -63,6 +63,7 @@
     unsigned                         cached:1;
     unsigned                         transparent:1;
     unsigned                         so_keepalive:1;
+    unsigned                         down:1;
 
                                      /* ngx_connection_log_error_e */
     unsigned                         log_error:2;