Description of problem: Addresses post-merge review comments for https://review.gluster.org/#/c/glusterfs/+/20095/
REVIEW: https://review.gluster.org/22543 (afr: thin-arbiter lock release fixes) posted (#1) for review on master by Ravishankar N
REVIEW: https://review.gluster.org/22543 (afr: thin-arbiter lock release fixes) merged (#8) on master by Pranith Kumar Karampuri