Update CHANGES.txt -- just adding a link since JIRA won't let me download more than 100 issues.... Also add some doc to make_rc.sh script

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.96@1525295 13f79535-47bb-0310-9956-ffa450edef68
Update CHANGES.txt -- just adding a link since JIRA won't let me download more than 100 issues.... Also add some doc to make_rc.sh script

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.96@1525296 13f79535-47bb-0310-9956-ffa450edef68