lib/storage/sync-updates.js
function(datasetId, acknowledgement, callback) {
      return metrics.timeAsyncFunc(metrics.KEYS.MONGODB_OPERATION_TIME, doFindAndDeleteUpdate)(datasetId, acknowledgement, callback);
    }
function(datasetId, acknowledgement, callback) {
      return metrics.timeAsyncFunc(metrics.KEYS.MONGODB_OPERATION_TIME, doFindAndDeleteUpdate)(datasetId, acknowledgement, callback);
    }
find the delete the given sync update
@param {String} datasetId
@param {storage~Acknowledgement} acknowledgement
@param {Function} callback