Flag/switch to disable keep-alives

[shin-nien]

We deploy docker_auth configured to use ext_auth.sh into Kubernetes where we see an uneven distribution of requests (most likely due to kube-proxy) and eventually we hit an upper limit of how much docker_auth can fork to call ext_auth.sh.

Disabling keep-alives at least allows us to scale horizontally so this issue is to add a flag to do just that. In our testing, disabling keep-alives makes the load more evenly distributed.

At the moment we're patching docker_auth but we'll try and get a PR together at some point.

[rojer]

makes sense, go ahead