Ensure xenial base image present before building proxy_init (#11277)
Ensure xenial base image present before building proxy_init (#11277)


geeknoid/istio,istio/istio,smawson/istio,istio/istio,smawson/istio,geeknoid/istio,smawson/istio,geeknoid/istio,smawson/istio,geeknoid/istio,geeknoid/istio,smawson/istio,istio/istio,geeknoid/istio,istio/istio,istio/istio,smawson/istio