os: deal with chmod error for TestRootConsistencyChmod
Previously the error returned by chmod has not actually been used.
Change-Id: I97c947a2278a084c58784fd100630ce2a54bfb03
GitHub-Last-Rev:
ddc60a044f641d264c9ee88d87b2da7e2f766741
GitHub-Pull-Request: golang/go#71744
Reviewed-on: https://go-review.googlesource.com/c/go/+/649418
Reviewed-by: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>