cvmfs/cvmfs — pull request #559 by DrDaveD (2014-10-02 16:22:56+00:00)
Title: use link/unlink instead of rename when using alien cache, for nfs' sake

We found when using an alien cache on NFS that a rename() from a second client's download of a cached object would trash the file handle that the first client had, giving the first client a stale file handle. So when using alien cache, instead of doing a rename(), do a link() followed by an unlink() and ignore if link gets an EEXISTS error.