[isolated] use luci errors
[isolated] use luci errors

Change-Id: I42d9c3cc8760602ec481d700b6e2e155ae34eec3
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-go/+/2396835
Auto-Submit: Takuto Ikuta <71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org>
Commit-Queue: Junji Watanabe <aaef61ef98ffea505db831f310be2a0eb8492537@google.com>
Reviewed-by: Junji Watanabe <aaef61ef98ffea505db831f310be2a0eb8492537@google.com>

luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go