Move And Inline Method	package addSnapshotDiff(snapshot Snapshot, dir INodeDirectory, isSnapshotCreation boolean) : DirectoryDiff moved from class org.apache.hadoop.hdfs.server.namenode.snapshot.INodeDirectoryWithSnapshot.DirectoryDiffList to class org.apache.hadoop.hdfs.server.namenode.snapshot.INodeDirectorySnapshottable & inlined to package addSnapshot(id int, name String) : Snapshot