Adam Anderson

If anyone else runs into this issue, I found what seems to be a simple workaround (specifically on `r1.15` branch) The issue is that [`tensorflow_serving/apis/prediction_log.proto`](https://github.com/tensorflow/serving/blob/master/tensorflow_serving/apis/prediction_log.proto) needs a `LogMetadata` from [`tensorflow_serving/core/logging.proto`](https://github.com/tensorflow/serving/blob/r1.15/tensorflow_serving/core/logging.proto),...