Do a basic sanity check that dirents returned via fuse are kind of sane.

Do a basic sanity check that dirents returned via fuse are kind of sane.

Ensure that file names passed back by readdir do not include a '/'
character. The '/' char is the path separator and is not allowed in
any filename. On top of this also check that d_reclen and d_namlen
are kind of sane and zero out the padding bytes after d_name.

OK beck@