3.0.11.1 regression: HTTPd fails to send response when processing handler callback

There aren't a whole lot of in-tree users, but you can test with the /art handler of the web interface. On 3.0.11 it would return the text/plain document Error (or some art). On 3.0.11.1 the HTTPd shuts the connection down without sending any response - the callback is still executed.

Reverting the string of 7 commits on the HTTPd from c40e0a52 to dbcfd767 fixes the issue.