Maintains full backward compatibility.
Use swift_proxy_config ini provider to mange proxy-server.conf.
Remove all erb templates. Move all template logic into proxy
middleware classes. To purge proxy.conf of settings that are
not specified set the new paramater "purge_config" to "true".
Change-Id: I0a143cf812043ea0f9a008a6e5c60ec87f9a4e9a
60ed2ee79c