HDFS-6618. FSNamesystem#delete drops the FSN lock between removing INodes from the tree and deleting them from the inode map (kihwal via cmccabe)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1609381 13f79535-47bb-0310-9956-ffa450edef68
HDFS-6622. Rename and AddBlock may race and produce invalid edits (kihwal via cmccabe)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1609386 13f79535-47bb-0310-9956-ffa450edef68