SOLR-5897: modify CHANGES.txt, backport to 4.8
SOLR-5897: modify CHANGES.txt, backport to 4.8

git-svn-id: 308d55f399f3bd9aa0560a10e81a003040006c48@1588914 13f79535-47bb-0310-9956-ffa450edef68

apache/solr,apache/solr,apache/solr,apache/solr,apache/solr