[autoroll] Truncate NotRolledRevisions, use skerr in go/roller package
[autoroll] Truncate NotRolledRevisions, use skerr in go/roller package

Change-Id: I1d4afc07a05b5a1cb51c3813ae86d0ea01cf987c
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/251916
Commit-Queue: Eric Boren <0e499112533c8544f0505ea0d08394fb5ad7d8fa@google.com>
Reviewed-by: Ravi Mistry <9fa2e7438b8cb730f96b74865492597170561628@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