fix connection counter in subrequests

src/http/modules/ngx_http_limit_zone_module.c

diff --git a/src/http/modules/ngx_http_limit_zone_module.c b/src/http/modules/ngx_http_limit_zone_module.c
index caed09c..1ec99cc 100644
--- a/src/http/modules/ngx_http_limit_zone_module.c
+++ b/src/http/modules/ngx_http_limit_zone_module.c
@@ -131,7 +131,7 @@
         return NGX_DECLINED;
     }
 
-    r->limit_zone_set = 1;
+    r->main->limit_zone_set = 1;
 
     len = vv->len;