LU-16268 mdd: set effective changelog mask correctly

LU-16268 mdd: set effective changelog mask correctly

When changelog mask is changed from MINMASK to a particular
value then recalculation is missed, so effective mask could
stay unchanged against expectations.

Patch adds additional check that old mask is MINMASK or not
to decide if mask recalculation is needed.

Test 160o is extended for that issue.

Fixes: ffe259f81cda ("LU-13055 changelog: use default mask if server has no mask")
Signed-off-by: Mikhail Pershin <mpershin@whamcloud.com>
Change-Id: Ia3c93e19daeb71ff1042ebdb555e918faf89f844
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/48961
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Emoly Liu <emoly@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>