Force HTTP connection closure after each request

This is an unfortunately intrusive approach, but it is the best
I could find quickly. The usual approach of including a
"Connection: close" header didn't seem to work. This work is likely
needed in all other drivers.
Don't close S3 connections with a stream response

I was overzealous in 2fb90e1ff4240d1
Merge pull request #126 from maksimov/develop

Force HTTP connection closure after each request - porting from 2013.07