Codehosting fails to release old connections when use_forking_daemon: True

This is a follow up from the earlier "leaked handles". We tried enabling it again, but it yet again saw the number of connections continue to increase. Many connections connected and were released successfully, but somehow we would get ones that did not cleanup.
I'm marking this as a new bug, because the actual file handle leaks were fixed.

note that before we try this rollout again, we want to have switched over to a multi-server system, using haproxy. That way we can try one server in a new mode, without disrupting connectivity.