Fix mapper lint error

[wbc6080]

What type of PR is this?
/kind bug

What this PR does / why we need it:

Fix lint error in mapper-framework.

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

[kubeedge-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by:
To complete the pull request process, please assign fisherxu after the PR has been reviewed.
You can assign the PR to them by writing /assign @fisherxu in a comment when ready.

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files:

• staging/src/github.com/kubeedge/mapper-framework/OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[wbc6080]

cc @luomengY @WillardHu @fisherxu

[luomengY]

/lgtm

[Shelley-BaoYue]

CI cannot check lint error in mapper? Can we add lint check for mapper in CI?

[wbc6080]

CI cannot check lint error in mapper? Can we add lint check for mapper in CI?

We have previously added mapper checks to lint. https://github.com/kubeedge/kubeedge/blob/master/hack/lib/lint.sh#L81 The currently problem code is located in the _template directory of mapper-framework. This part is the mapper template and cannot be compiled and run normally, which should be the reason why lint cannot check it. Only after executing make generate to generate the mapper project can this part of the code run normally. I will see if there is a suitable solution later.