httpd: let the login page fetch its translations

login.html asks for i18n.js, but the file is not on the short list a
client may have before it authenticates, so the request is answered with
a redirect back to the login page and the strings stay as the English
that is baked into the markup.

The file carries only the interface text, the same text the page already
ships untranslated, so serving it before login gives nothing away.

httpd/httpd.c

@@ -994,6 +994,7 @@ void httpd_appcall(void)
 			if (!authenticated && !(f_data[entry].start == FDATA_START_login_html 
 						|| f_data[entry].start == FDATA_START_port_svg 
 						|| f_data[entry].start == FDATA_START_sfp_svg
+						|| f_data[entry].start == FDATA_START_i18n_js
 						|| f_data[entry].start == FDATA_START_style_css)) {
 				send_to_login();
 				goto do_send;