corrected CHANGES.txt for MAPREDUCE-4572 incorrectly recorded as a HADOOP bug in 1.2.0

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-1@1479462 13f79535-47bb-0310-9956-ffa450edef68
corrected CHANGES.txt to show HDFS-2751 fixed in 1.1.0 rather than 1.2.0.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-1@1479463 13f79535-47bb-0310-9956-ffa450edef68
corrected jira reference to HDFS-4062 from HDFS-3062 in 1.2.0

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-1@1479464 13f79535-47bb-0310-9956-ffa450edef68