Fix golint errors

[andyi2it]

What this PR does / why we need it:

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #3608

Type of changes
Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

1. Please confirm that if this PR changes any image versions, then that's the sole change this PR makes.

Checklist:

• Have you added unit/e2e tests that prove your fix is effective or that this feature works?
• Has code been commented, particularly in hard-to-understand areas?
• Have you made corresponding changes to the documentation?

Release note:

NONE

[yuzisun]

/lgtm
/approve

[oss-prow-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: andyi2it, yuzisun

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