LU-13840 utils: --pool instead of -o with lfs setquota

LU-13840 utils: --pool instead of -o with lfs setquota

The use of "lfs setquota -o" as the short option for
specifying the quota pool is confusing, because "lfs quota -o"
is the short option for getting quota on an OST. Use only
long option --pool for lfs setquota.

Patch also changes -o with --pool for setquota in
sanity-quota.sh

Change-Id: I18a695dcbbcd668611b1301c48f4e10d354b2686
Signed-off-by: Sergey Cheremencev <sergey.cheremencev@hpe.com>
Reviewed-on: https://review.whamcloud.com/39715
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>