Create unit test for create cluster operation with correct defaults via RESTAPI

[Nastya Urlapova]

By default via REST API Nailgun create cluster with incorrect defaults, for example network provider:
curl -H "X-Auth-Token: e0fb383ae1054b379b635ce2b691a81e" -X POST -d '{"tasks": [], "name": "123121233", "release_id": 2, "nodes": []}' http://10.109.5.2:8000/api/v1/clusters/
{"status": "new", "is_customized": false, "release_id": 2, "ui_settings": {"sort": [{"roles": "asc"}], "sort_by_labels": [], "search": "", "filter_by_labels": {}, "filter": {}, "view_mode": "standard"}, "fuel_version": "8.0", "net_provider": "nova_network", "mode": "ha_compact", "pending_release_id": null, "changes": [{"node_id": null, "name": "attributes"}, {"node_id": null, "name": "networks"}, {"node_id": null, "name": "vmware_attributes"}], "id": 2, "name": "123121233"}

By default it should be neutron network provider instead of nova. We should check it with unittest for Nailgun REST API.

VERSION:
  feature_groups:
    - mirantis
  production: "docker"
  release: "8.0"
  openstack_version: "2015.1.0-8.0"
  api: "1.0"
  build_number: "140"
  build_id: "140"
  fuel-nailgun_sha: "46fbd9e21e91af057335cfa7e1f29159c1eb82ac"
  python-fuelclient_sha: "769df968e19d95a4ab4f12b1d2c76d385cf3168c"
  fuel-agent_sha: "84335446172cc6a699252c184076a519ac791ca1"
  fuel-nailgun-agent_sha: "d66f188a1832a9c23b04884a14ef00fc5605ec6d"
  astute_sha: "e99368bd77496870592781f4ba4fb0caacb9f3a7"
  fuel-library_sha: "6579c3debf9f1e8832cc6714aca0125b66d2bd7d"
  fuel-ostf_sha: "983d0e6fe64397d6ff3bd72311c26c44b02de3e8"
  fuel-createmirror_sha: "df6a93f7e2819d3dfa600052b0f901d9594eb0db"
  fuelmain_sha: "4c58b6503fc780be117777182165fd7b037b1a96"

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/234113
Committed: https://git.openstack.org/cgit/stackforge/fuel-web/commit/?id=3533ae59bc5c3d25b3599cb9203a6503f4cf03de
Submitter: Jenkins
Branch: master

commit 3533ae59bc5c3d25b3599cb9203a6503f4cf03de
Author: Igor Kalnitsky <email address hidden>
Date: Tue Oct 13 13:17:04 2015 +0300

    Change default network provider to Neutron

    In previous release (Fuel 7.0) nova-network is became deprecated, and
    that means it will be dropped in Fuel 8.0. So let's change default to
    neutron, because IIUC nova-network is already removed from
    fuel-library's master and some swarm tests are broken.

    Closes-Bug: #1503657
    Closes-Bug: #1505258

    Change-Id: I65a0ca2906503cb9c83fd99fddda9a8ee5156b16