build: fix govet shadow err

[ghouscht]

Fix for the govet error reported here: https://github.com/etcd-io/etcd/pull/18854#issuecomment-2464461492

Please read https://github.com/etcd-io/etcd/blob/main/CONTRIBUTING.md#contribution-flow.

[k8s-ci-robot]

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[codecov-commenter]

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Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.

Project coverage is 68.76%. Comparing base (b125409) to head (1fbf0e4).

:exclamation: Current head 1fbf0e4 differs from pull request most recent head 97d19b6

Please upload reports for the commit 97d19b6 to get more accurate results.

Files with missing lines	Patch %	Lines
server/storage/backend/backend.go	0.00%	2 Missing :warning:

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Additional details and impacted files

| [Files with missing lines](https://app.codecov.io/gh/etcd-io/etcd/pull/18857?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None) | Coverage Δ | | |---|---|---| | [server/storage/backend/backend.go](https://app.codecov.io/gh/etcd-io/etcd/pull/18857?src=pr&el=tree&filepath=server%2Fstorage%2Fbackend%2Fbackend.go&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None#diff-c2VydmVyL3N0b3JhZ2UvYmFja2VuZC9iYWNrZW5kLmdv) | `81.08% <0.00%> (ø)` | | ... and [22 files with indirect coverage changes](https://app.codecov.io/gh/etcd-io/etcd/pull/18857/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None) ```diff @@ Coverage Diff @@ ## main #18857 +/- ## ========================================== + Coverage 68.73% 68.76% +0.03% ========================================== Files 420 420 Lines 35531 35531 ========================================== + Hits 24422 24434 +12 + Misses 9683 9668 -15 - Partials 1426 1429 +3 ``` ------ [Continue to review full report in Codecov by Sentry](https://app.codecov.io/gh/etcd-io/etcd/pull/18857?dropdown=coverage&src=pr&el=continue&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None). > **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None) > `Δ = absolute (impact)`, `ø = not affected`, `? = missing data` > Powered by [Codecov](https://app.codecov.io/gh/etcd-io/etcd/pull/18857?dropdown=coverage&src=pr&el=footer&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None). Last update [b125409...97d19b6](https://app.codecov.io/gh/etcd-io/etcd/pull/18857?dropdown=coverage&src=pr&el=lastupdated&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None).

[ahrtr]

/ok-to-test

[ghouscht]

/retest

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ahrtr, ghouscht, jmhbnz

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Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/etcd-io/etcd/blob/main/OWNERS)~~ [ahrtr,jmhbnz] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment