LU-930 ofd: improve orphan cleaning message

LU-930 ofd: improve orphan cleaning message

Reword the orphan cleaning message, happening
at each MDT connection after OST start to make it less
scary and implies a bit more this is just normal thing
going on.

Test-Parameters: trivial

Change-Id: I7b4d726b1e96fe8d39872df5ed85453c99ccdc6a
Signed-off-by: Aurelien Degremont <adegremont@nvidia.com>
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/54639
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>