HDFS-4993. fsck can fail if a file is renamed or deleted. Contributed by Robert Parker.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1512456 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-9757. Har metadata cache can grow without limit (Cristina Abad via daryn)


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1512470 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/branch-0.23' into branch-0.23-gd
Merge remote branch 'origin/branch-0.23-gd' into fb-HADOOP-9078-branch-0.23-gd