Retry operations that have been shown to throw EINTR
errors on CIFS.
Todo: Solution for this pain in the back:
warning: unix.Getdents returned errno 2 in the middle of data
rm: cannot remove 'linux-3.0.old3/Documentation/ABI/removed': Input/output error
Progress towards fixing https://github.com/rfjakob/gocryptfs/issues/483 .
Jakob Unterwurzacher