MRC: fixed bug that caused invalid reads/writes on a striped file when the...

MRC: fixed bug that caused invalid reads/writes on a striped file when the file were previously linked/renamed

git-svn-id: https://xtreemfs.googlecode.com/svn/trunk@848 f8528748-c2c0-11dd-ba5c-d3b7c2b3b534