vfs_fruit: use correct case FRUIT_RSRC_STREAM in readdir_attr_rfork_size()

vfs_fruit: use correct case FRUIT_RSRC_STREAM in readdir_attr_rfork_size()

This is a genuine bug, but luckily this would only impact configs which nobody
uses:

  fruit:metadata = netatalk
  fruit:resource = stream

With the above configuration the switch in readdir_attr_rfork_size() would hit
the default case and so always report resource forks as 0 bytes in size.

All deployment that I've seen that use fruit:resource=stream also use
fruit:metadata=stream, so the switch takes FRUIT_META_STREAM case which runs the
correct code readdir_attr_rfork_size_stream().

Bug: https://bugzilla.samba.org/show_bug.cgi?id=13968

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
(cherry picked from commit 83179a74119de84d20f796c241aae6bccb83a68b)