Add ARCHIVAL storage type
Temp commit HDFS-6362.03.patch
Merge remote-tracking branch 'apache/trunk' into archival
Allow storing StorageType hint with UnderReplicatedBlocks (inefficient, first cut)
Merge remote-tracking branch 'apache/trunk' into archival
Expose BlockWithStorageHints to users of UnderReplicatedBlocks (they don't use it yet)
Pass storage hint to block placement policy. It is not respected by the block placement policy yet, nor by the DataNode
Decommission should pass correct StorageType hint to UnderReplicatedBlocks
PendingReplicationBlocks tracks StorageType hint and propagates it to UnderReplicatedBlocks
Merge remote-tracking branch 'apache/trunk' into archival
Merge preliminary changes from private branch