Cherry-pick #15649 to 7.x: [metricbeat] Add divide by zero check to docker/diskio#15706

fearful-symmetry merged 2 commits intoelastic:7.xelastic/beats:7.xfrom

fearful-symmetry:backport_15649_7.xfearful-symmetry/beats:backport_15649_7.xCopy head branch name to clipboard