util: fix vet

[jackysp]

Signed-off-by: Shuaipeng Yu jackysp@gmail.com

What problem does this PR solve?

Issue Number: close #xxx

Problem Summary:
Go vet failed.

What is changed and how it works?

Proposal: xxx

What's Changed:
Fix it.

How it Works:

Related changes

• PR to update pingcap/docs/pingcap/docs-cn:
• Need to cherry-pick to the release branch

Check List

Tests

• Manual test

Run go vet task.

Release note

• No release note

[lysu]

/lgtm

[coocood]

/LGTM

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• coocood
• lysu

To complete the pull request process, please ask the reviewers in the list to review by filling /cc @reviewer in the comment.
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[jackysp]

/merge

[ti-chi-bot]

@jackysp: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

You only need to trigger /merge once, and if the CI test fails, you just re-trigger the test that failed and the bot will merge the PR for you after the CI passes.

If you have any questions about the PR merge process, please refer to pr process.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 0ff3368

[lysu]

caused by new vet added by go1.6 golang/go#40701

[ti-chi-bot]

@jackysp: Your PR was out of date, I have automatically updated it for you.

At the same time I will also trigger all tests for you:

/run-all-tests

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.