Allow distro-es to bind to a specific interface

We have an embedded elasticsearch instance/cluster as part of the apiman default distro:

https://github.com/apiman/apiman/blob/master/distro/es/src/main/java/io/apiman/distro/es/Bootstrapper.java#L57-L64

Currently it cannot bind to a specific network interface, making it a challenge to run in e.g. openshift. The bind interface can be set via elastic settings:

https://www.elastic.co/guide/en/elasticsearch/reference/1.6/modules-network.html