Strip externalIPs from services with type==LoadBalancer

[sseago]

For load-balanced services (i.e. spec.Type=="LoadBalancer"), externalIPs is set automatically by openshift/kubernetes. On restore, the old value isn't updated to reflect the new cluster's environment. If externalIPs are disabled, the result is a failed service restore. If they are enabled, then the result is just the wrong value for the resource.

At a minimum, we should strip externalIPs when type is LoadBalancer, since kubernetes will regenerate the value on restore.

For manually-managed externalIPs, we probably shouldn't do anything automatic, but we should document the issue. Users will need to check and potentially update these post-migration, and if they have externalIPs in the src cluster but have not enabled them in the dest cluster, they probably need to remove them prior to migrating.