LU-17000 misc: Fix Unused Value error(0)

LU-17000 misc: Fix Unused Value error(0)

This patch fixes unused value error reported
by coverity run.

CoverityID: 397913 ("Unused value"): lquota_disk.c
CoverityID: 397912 ("Unused value"): libmount_utils_zfs.c

Test-Parameters: trivial fstype=zfs testlist=sanity-quota,conf-sanity,sanity
Signed-off-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Change-Id: I509592ddc9b8fa3e9a6a7dcef4e476ad4fc9d9fc
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/52216
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Timothy Day <timday@amazon.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>