EX-7600 osd: save compressed object size on zfs

EX-7600 osd: save compressed object size on zfs

"osc: save compressed object size" added means to transfer
object size to the osd and added ldiskfs support.

This patch adds saving objec size to the ZFS backend.
Currently this fix submitted as separete patch, for
testing purpouse, but can be marged to the main patch latter.

Signed-off-by: Artem Blagodarenko <ablagodarenko@ddn.com>
Test-Parameters: trivial testlist=sanity fstype=zfs
Change-Id: I99e29e3f756a070b5f3cece12c4ca58f668a2ecf
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/52958
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Patrick Farrell <pfarrell@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>