Delete samples for Trace (#957)
Delete samples for Trace (#957)

Trace samples are in
https://github.com/googleapis/cloud-trace-nodejs/blob/master/samples/app.js
GoogleCloudPlatform/nodejs-docs-samples,GoogleCloudPlatform/nodejs-docs-samples,GoogleCloudPlatform/nodejs-docs-samples,GoogleCloudPlatform/nodejs-docs-samples