Disable cloud trace for envoy prototype.

[chowchow316]

To prevent envoy crush if removing api_manager cluster from envoy-esp.conf.

[kyessenov]

You can drop api_manager from envoy.conf now.

[chowchow316]

I remember Lizan wanted to retain api_manager in envoy-esp.conf. Do we still need it @lizan?

[lizan]

I'd prefer keeping it but either is fine since the file is for local testing only. api_manager is still needed if you enable auth and/or metadata.

[chowchow316]

Okay, will keep it for now, we can remove it later if needed.

[qiwzhang]

Let us remove "api_manager". If auth is added, we can add it back as "auth_pkey_server", same for meta data server

[lizan]

Remove once RunHTTPRequest is no longer hardcoded with "api_manager"?

[qiwzhang]

You are right. It is still hardcoded in RunHTTPRequest. We can use a separate PR to change RunHTTPRequest to get host name out of URL, make it as cluster name. and remove "ap_manager" or change it to whatever it is needed.

[kyessenov]

I'd prefer if we did not need api_manager for the mixer client build of ESP.
That means removing the api_manager cluster definition (presently, removing it may cause a segfault depending on the api_manager features.)
We can have another build that has api_manager.