Automatic merge from submit-queue
GCI: fix the issue #26379
This PR deletes docker0 explicitly to fix the issue. In some cases, coexistence of docker0 and cbr0 make troubles in GCI-based cluster instances.
I verified it in GKE. With the fix, fluentd-gcp pod shows no error. "curl google.com" can work inside a pod. Mark it as P0 to match the issue priority.
@a-robinson @roberthbailey @freehan @kubernetes/goog-image