[release] Prepare XE 1.9RC1 release.
[release] Prepare XE 1.9RC1 release.

git-svn-id: eea26612969e16cfeea121ea268596bb181b6a2a@20441 f329d543-caf0-0310-9063-dda96c69346f

xwiki/xwiki-platform,pbondoer/xwiki-platform,xwiki/xwiki-platform,xwiki/xwiki-platform,pbondoer/xwiki-platform,pbondoer/xwiki-platform,pbondoer/xwiki-platform,pbondoer/xwiki-platform,xwiki/xwiki-platform,xwiki/xwiki-platform