LU-10922 osd-zfs: return -ENOENT if object destoryed

LU-10922 osd-zfs: return -ENOENT if object destoryed

Originally, if the target object does not exist or just destroyed,
the osd_xattr_get_internal() will return -ENOENT to the caller, it
is right. But one of the callers: osd_xattr_get(), converts it as
-ENODATA before returning to the upper layer by wrong.

This patch fixes it.

Signed-off-by: Fan Yong <fan.yong@intel.com>
Change-Id: I9bfd03c53dda165af37a4ae62b4efbc5875833e5
Reviewed-on: https://review.whamcloud.com/32042
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>