Fix a panic in GetContainersResources()

[rsgowman]

What type of PR is this?

/kind bug

What this PR does / why we need it:

The panic occurs when VPA is set to control only the resource Requests (rather than the default of both Requests and Limits).

Which issue(s) this PR fixes:

No issue filed.

Special notes for your reviewer:

n/a

Does this PR introduce a user-facing change?

NONE

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

n/a

[k8s-ci-robot]

Hi @rsgowman. Thanks for your PR.

I'm waiting for a kubernetes 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.

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[rsgowman]

/assign @raywainman

[adrianmoisey]

/ok-to-test

[raywainman]

/lgtm

/approve

Gahh, my bad on this one, thanks for the fix!

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: raywainman, rsgowman

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