vfs_fruit: remove check for number of xattrs from ad_convert_xattr

vfs_fruit: remove check for number of xattrs from ad_convert_xattr

Turns out that there exist AppleDouble files with an extended FinderInfo
entry that includes the xattr marshall buffer, but the count of xattrs
in the buffer is just zero.

We do want to discard this extended FinderInfo entry and convert it to a
simple fixed size FinderInfo entry, so remove the check.

Bug: https://bugzilla.samba.org/show_bug.cgi?id=13649

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>