fix spelling mistakes

[tanshanshan]

What this PR does / why we need it:
fix spelling mistakes
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 #

Special notes for your reviewer:

Release note:

NONE

[CaoShuFeng]

/lgtm

[tanshanshan]

/test pull-kubernetes-e2e-gce-100-performance

[k8s-github-robot]

/test all

Tests are more than 96 hours old. Re-running tests.

[tanshanshan]

/test pull-kubernetes-integration

[nikhita]

/assign @thockin
for approval

[thockin]

Are there going to be more of these spelling PRs? Can we get one mondo PR with all of them?

[thockin]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: tanshanshan, thockin

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[k8s-ci-robot]

@tanshanshan: The following test failed, say /retest to rerun them all:

Test name	Commit	Details	Rerun command
pull-kubernetes-integration	a83c4db	link	/test pull-kubernetes-integration

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

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