HDFS-4352. Encapsulate arguments to BlockReaderFactory in a class. Contributed by Colin Patrick McCabe.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1428729 13f79535-47bb-0310-9956-ffa450edef68
HDFS-4270. Introduce soft and hard limits for max replication so that replications of the highest priority are allowed to choose a source datanode that has reached its soft limit but not the hard limit.  Contributed by Derek Dagit


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1428739 13f79535-47bb-0310-9956-ffa450edef68
Merge branch 'trunk' of github.com:griddynamics/yhadoop-common into trunk-gd
Merge branch 'trunk-gd' of github.com:griddynamics/yhadoop-common into fb-HADOOP-8849-trunk-gd