Fix Rolling update CI issue in teardown

[homernajafi]

Only teardown the cluster if exists.

[helmsman-bot]

Can one of the admins verify this patch?

[googlebot]

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[google-oss-robot]

Hi @homernajafi. Thanks for your PR.

I'm waiting for a GoogleCloudPlatform member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[googlebot]

CLAs look good, thanks!

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[chrislovecnm]

/lgtm
/approve

[chrislovecnm]

/approve
/lgtm

[chrislovecnm]

test this please

[google-oss-robot]

New changes are detected. LGTM label has been removed.

[google-oss-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: chrislovecnm, homernajafi

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Needs approval from an approver in each of these files:

• OWNERS [chrislovecnm]

Approvers can indicate their approval by writing /approve in a comment
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[google-oss-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: chrislovecnm, homernajafi

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

The pull request process is described here

Details

Needs approval from an approver in each of these files:

• OWNERS [chrislovecnm]

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

[homernajafi]

test this please