rgw: s3website doesn't prefetch for web_dir() check

this function only needs to check for existence of the given path.
the sal::Object is destroyed before the function returns, so it's
wasteful to prefetch its data

Fixes: https://tracker.ceph.com/issues/62938

Signed-off-by: Casey Bodley <cbodley@redhat.com>

src/rgw/rgw_rest_s3.cc

@@ -5282,7 +5282,6 @@ bool RGWHandler_REST_S3Website::web_dir() const {
   std::unique_ptr<rgw::sal::Object> obj = s->bucket->get_object(rgw_obj_key(subdir_name));
 
   obj->set_atomic();
-  obj->set_prefetch_data();
 
   RGWObjState* state = nullptr;
   if (obj->get_obj_state(s, &state, s->yield) < 0) {