Kubernetes executor should expose services via HostAliases
Description
Job services are always exposed on localhost instead of service name (or alias) when running on k8s.
Moving a working job definition form a docker executor to a k8s executor will likely fail if services are involved.
Proposal
If running on k8s >= 1.7 we should create Pods with HostAliases pointing each defined service to 127.0.0.1.