charset could not be set for ngx_http_autoindex_module responses

src/http/modules/ngx_http_autoindex_module.c

diff --git a/src/http/modules/ngx_http_autoindex_module.c b/src/http/modules/ngx_http_autoindex_module.c
index f5944c4..e08e63c 100644
--- a/src/http/modules/ngx_http_autoindex_module.c
+++ b/src/http/modules/ngx_http_autoindex_module.c
@@ -229,6 +229,7 @@
     }
 
     r->headers_out.status = NGX_HTTP_OK;
+    r->headers_out.content_type_len = sizeof("text/html") - 1;
     r->headers_out.content_type.len = sizeof("text/html") - 1;
     r->headers_out.content_type.data = (u_char *) "text/html";