s3-vfs: Use ENOATTR in errno comparison for getxattr

s3-vfs: Use ENOATTR in errno comparison for getxattr

* ENODATA is not defined in FreeBSD
* ENOATTR is defined to be a synonym for ENODATA in Linux
* In its absence Samba already defines ENOATTR to either
  ENODATA or ENOENT

Thus it is safe and correct to compare with ENOATTR rather
than ENODATA.

Signed-off-by: Anoop C S <anoopcs@redhat.com>
Reviewed-by: Uri Simchoni <uri@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Wed Jan 23 21:59:10 CET 2019 on sn-devel-144