Improve otel collector/jaeger pipeline compatibility

[joe-elliott]

Using jaeger-debug-id has an issue that reveals an incompatibility between otel-collector and the jaeger pipeline. jaeger-debug-id generates spans with invalid refs which are dropped by the otel-collector but are passed and stored by the Jaeger pipeline/backend.

To increase compatibility with the jaeger processing pipeline we'd like to pass/store spans that have these invalid refs.

[joe-elliott]

The following was removed from the original issue in favor of #502.

Add logging to increase visibility on this issue. Currently these dropped lines are metric'ed but nothing is logged:

opentelemetry-collector/exporter/jaeger/jaegergrpcexporter/exporter.go

Lines 71 to 74 in b468dee

	protoBatch, err := jaegertranslator.OCProtoToJaegerProto(td)
	if err != nil {
	return len(td.Spans), consumererror.Permanent(err)
	}