HDFS-7365. Remove hdfs.server.blockmanagement.MutableBlockCollection. Contributed by Li Lu.
MAPREDUCE-5958. Wrong reduce task progress if map output is compressed. Contributed by Emilio Coppa and Jason Lowe.
(cherry picked from commit 8f701ae07a0b1dc70b8e1eb8d4a5c35c0a1e76da)