Allow to disable keepalive

There's a race condition when a client makes a request "at the same
time" the HTTP connection is being closed by Apache because the
`KeepAliveTimeout` is expired.

This is explained in detail and can be reproduce using
https://github.com/mikem23/keepalive-race or
https://github.com/JordanP/openstack-snippets/blob/master/keepalive-race/keep-alive-race.py

Just disable KeepAlive to fix the
('Connection aborted.', BadStatusLine("''",)) error we are seeing.

Related-Prod: PROD-18148

Change-Id: I1061a937f6bca11ffb556604c216bf11c6db4006
2 files changed