Fix CHANGES.txt to reflect the twisted evolution and current state of the Admin UI "Files" conf directory File Browser.  Moved issue descriptions to the 5.0 section for the trunk-only - but currently disabled (see SOLR-5539) - ability to create and modify files in the conf dir.
Fix CHANGES.txt to reflect the twisted evolution and current state of the Admin UI "Files" conf directory File Browser.  Moved issue descriptions to the 5.0 section for the trunk-only - but currently disabled (see SOLR-5539) - ability to create and modify files in the conf dir.

git-svn-id: 308d55f399f3bd9aa0560a10e81a003040006c48@1570764 13f79535-47bb-0310-9956-ffa450edef68

cscorley/solr-only-mirror,cscorley/solr-only-mirror,cscorley/solr-only-mirror