set "Content-Length: 0" for errors handled by "return 204"

src/http/ngx_http_script.c

diff --git a/src/http/ngx_http_script.c b/src/http/ngx_http_script.c
index 3a9e2a8..e8bce19 100644
--- a/src/http/ngx_http_script.c
+++ b/src/http/ngx_http_script.c
@@ -841,6 +841,7 @@
 
     if (code->status == NGX_HTTP_NO_CONTENT) {
         e->request->header_only = 1;
+        e->request->zero_body = 1;
     }
 
     e->ip += sizeof(ngx_http_script_return_code_t) - sizeof(uintptr_t);