libextreemfs: some vivaldi-specific changes (optional dir-updates, actually...

libextreemfs: some vivaldi-specific changes (optional dir-updates, actually used vivaldi-coords in openRequest and xtreemfs_update_file_sizeRequest, ..

git-svn-id: https://xtreemfs.googlecode.com/svn/trunk@2955 f8528748-c2c0-11dd-ba5c-d3b7c2b3b534