Fixed mongo test to hit find path with no parent span
Fixed mongo test to hit find path with no parent span

matthewloring/cloud-trace-nodejs,keymetrics/vxx,googleapis/cloud-trace-nodejs,matthewloring/cloud-trace-nodejs,keymetrics/vxx,googleapis/cloud-trace-nodejs,ofrobots/cloud-trace-nodejs,matthewloring/cloud-trace-nodejs,t9nf/cloud-trace-nodejs,googleapis/cloud-trace-nodejs,keymetrics/trassingue,ofrobots/cloud-trace-nodejs,t9nf/cloud-trace-nodejs,keymetrics/trassingue,googleapis/cloud-trace-nodejs