Collectors.toMap uses a byte [] for key

Good one found by a jxray spelunking misha@cloudera.com.

The below added by HBASE-19496 is making hashmaps with byte []s for keys (byte []'s don't do hashCode/Equals; usually when we have byte []'s for keys, we do ConcurrentMap and pass a Comparator in constructor that knows how to do byte []s).

.setStoreSequenceIds(regionLoadPB.getStoreCompleteSequenceIdList().stream()
  .collect(Collectors.toMap(
    (ClusterStatusProtos.StoreSequenceId s) -> s.getFamilyName().toByteArray(),
      ClusterStatusProtos.StoreSequenceId::getSequenceId)))