fix return code

src/http/ngx_http_core_module.c

diff --git a/src/http/ngx_http_core_module.c b/src/http/ngx_http_core_module.c
index 574e925..84d8cc1 100644
--- a/src/http/ngx_http_core_module.c
+++ b/src/http/ngx_http_core_module.c
@@ -2912,7 +2912,7 @@
         if (conf->resolver == NULL) {
             conf->resolver = ngx_resolver_create(NULL, cf->cycle->new_log);
             if (conf->resolver == NULL) {
-                return NGX_OK;
+                return NGX_CONF_ERROR;
             }
         }
     }