We don't call klog.InitFlags yet, because that will cause a flag
redefinition error until we get everyone to stop using glog. That
will happen when we update to k8s 1.13.
The challenge here is that we normally only get the instance url. So we
have to do another call to GCE, but we also don't want to do one call
per instance.
Instead, we create a dump operation context object which we pass into the dump.