[datahopper] More uses of skerr in bot_metrics
[datahopper] More uses of skerr in bot_metrics

Change-Id: I5cf57aed963a1abeb8d3d4339895d71e220e586a
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/424297
Reviewed-by: Kevin Lubick <7cdab2cfab351f23814786ba39716e90eed69047@google.com>
Commit-Queue: Eric Boren <0e499112533c8544f0505ea0d08394fb5ad7d8fa@google.com>

google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot