Implement NovaFloatingIpAssociation res updatable

Implement handle_update for NovaFloatingIPAssociation
resource, allows to update NovaFloatingIpAssociation with
new server_id and new floatingip_id.

Change-Id: I75d361e2f0381f50ab83b54d752ffc080fe337fa
Implements: blueprint handle-update-for-floatingip
Merge "Implement NovaFloatingIpAssociation res updatable"
Implement OS::Sahara::Cluster resource

* This patch implements resource for Hadoop cluster provisioned by
  Sahara based on Sahara's cluster template.
* Heat template for stack based on this resource should have minimal set
  of fields needed to provision cluster.
* To successfully provision cluster the following steps should be done:
  - Sahara enabled and working in your env
  - Sahara contains valid cluster template [1]
  - Sahara's image registry contains registered image with preinstalled
    Hadoop components [2]

[1] http://docs.openstack.org/developer/sahara/restapi/rest_api_v1.0.html#create-cluster-template
[2] http://docs.openstack.org/developer/sahara/devref/quickstart.html#upload-image-to-glance

Related sahara's blueprint:
https://blueprints.launchpad.net/sahara/+spec/sahara-as-heat-resource

Co-Authored-By: Pavlo Shchelokovskyy <pshchelokovskyy@mirantis.com>

Implements: blueprint sahara-as-heat-resource

Change-Id: If470511cbb88349f47a61a35b1a19ba7c68efd83