Remove old DLO config remenents from proxy

Config items 'rate_limit_after_segment' and
'rate_limit_segments_per_sec' are configuration items left over from
before DLO was moved from the proxy server and into it's own
middleware. This change removes the configuration options from the
proxy server.

Change-Id: Ie3d42a57cda813feed019f01db986f13cdff9c31
Merge "Remove old DLO config remenents from proxy"