Fixed limit_req burst/nodelay inheritance (ticket #76).

The problem was introduced in r4381 (1.1.12).
diff --git a/src/http/modules/ngx_http_limit_req_module.c b/src/http/modules/ngx_http_limit_req_module.c
index 865f766..779b397 100644
--- a/src/http/modules/ngx_http_limit_req_module.c
+++ b/src/http/modules/ngx_http_limit_req_module.c
@@ -570,6 +570,8 @@
 
     if (conf->shm_zone == NULL) {
         conf->shm_zone = prev->shm_zone;
+        conf->burst = prev->burst;
+        conf->nodelay = prev->nodelay;
     }
 
     ngx_conf_merge_uint_value(conf->limit_log_level, prev->limit_log_level,