NEG Controller should skip and record event for endpoint without zone information

[freehan]

NEG controller use the translator to retrieve zone information associated with each endpoint via the corresponding node object. https://github.com/kubernetes/ingress-gce/blob/v1.5.1/pkg/controller/translator/translator.go#L188

It looks for annotation failure-domain.beta.kubernetes.io/zone on the node to determine the zone.
However, for some setup (manual), this information is not added to the node object. Hence the controller could not retrieve zone information for the endpoint. Causing NEG API failure.

[fejta-bot]

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[fejta-bot]

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[bowei]

/lifecycle frozen