There is no good reason to create a filestream when a directory entry
is created.  Delay it until the first allocation happens to simply
the code and reduce the amount of mru cache lookups we do.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>