disable "error_page 499 ..."

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 e7f54dd..8788dee 100644
--- a/src/http/ngx_http_core_module.c
+++ b/src/http/ngx_http_core_module.c
@@ -2884,7 +2884,7 @@
 
         err->status = ngx_atoi(value[i].data, value[i].len);
 
-        if (err->status == NGX_ERROR) {
+        if (err->status == NGX_ERROR || err->status == 499) {
             ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                "invalid value \"%V\"", &value[i]);
             return NGX_CONF_ERROR;