- When the user is not found in `reloadparam`, early return when the
user is not found to avoid calling `IsUserVisibleToViewer` which in turn
avoids causing a NPE.
- This fixes the case that a 500 error and 404 error is shown on the
same page.
- Add integration test for non-existant user RSS.
- Regression by c6366089df
(cherry picked from commit f0e0696278)
(cherry picked from commit 75d8066908)
4d0a1e0637