TSG-13912 支持对第三方设备健康检查

bfdd程序重启后, 支持将配置重新下发给bfdd程序

common/include/bfd.h

@@ -14,6 +14,8 @@ struct bfd_vtysh_client {
 
     // exec after connect server
     int (*pre_config)(struct bfd_vtysh_client *);
+    // recover config after connect server
+    int (*recover_config)(struct bfd_vtysh_client *);
 };
 
 int bfd_vtysh_connect(struct bfd_vtysh_client *client);