LU-14854 mdd: proper handle error in mdd_swap_layouts()

LU-14854 mdd: proper handle error in mdd_swap_layouts()

Only restore object's HSM xattr on error if it's for
SWAP_LAYOUTS_MDS_HSM.

Signed-off-by: Bobi Jam <bobijam@whamcloud.com>
Change-Id: I9d4c58cd3107c3900e72a0946d0ec7d7286dd43f
Reviewed-on: https://review.whamcloud.com/44319
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Lai Siyao <lai.siyao@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>