Fix "spinning wheel" when no README.md file in folder.

The rich workspace dialouge loads by default in every folder.
When user deletes README.md file, Nextcloud responds with 404 http code
to inform the UI scipts to not render the rich workspace.
Overwriting the response with custom 404 status page creates "spinning wheel" UI bug
in every folder without README.md file in it.

Fixes #318

conf/nginx.conf

@@ -57,7 +57,9 @@ location ^~ __PATH__/ {
 
   # Errors pages
   error_page 403 __PATH__/core/templates/403.php;
-  error_page 404 __PATH__/core/templates/404.php;
+  # Don't set custom 404 error page, as nextcloud uses 404 codes with meaningful payload.
+  # Setting custom 404 page clears the payload and creates UI bugs
+  # error_page 404 __PATH__/core/templates/404.php;
 
   location __PATH__/ {
     rewrite ^ __PATH__/index.php;