Updated release notes for HttpAsyncClient 4.1 release
Updated release notes for HttpAsyncClient 4.1 release

git-svn-id: 2de1178ee7e17b9e25ec88be7e3ec4b68f6c3a3a@1672333 13f79535-47bb-0310-9956-ffa450edef68

apache/httpasyncclient