fix misspelling in CHANGES.txt

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1504229 13f79535-47bb-0310-9956-ffa450edef68
YARN-922. Change FileSystemRMStateStore to use directories (Jian He via bikas)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1504261 13f79535-47bb-0310-9956-ffa450edef68
Commit OSX testing conveniences
HDFS-5000: Allow configuring storage medium for data directories.