Update prechecks for Ansible 2.0.0

[Vikram Hosakote]

In Newton, kolla master works only with Ansible 2.0.0 and does not work with Ansible 1.9.4, 1.9.5 and 2.1.0.

Hence, update prechecks to check if Ansbile version is 2.0.0.

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Below are the errors with Ansible 1.9.4 and 1.9.5:
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$ kolla-ansible deploy
TASK: [ceph | Copying over ceph.conf] *****************************************
Traceback (most recent call last):
  File "/usr/local/bin/ansible-playbook", line 324, in <module>
    sys.exit(main(sys.argv[1:]))
  File "/usr/local/bin/ansible-playbook", line 264, in main
    pb.run()
  File "/usr/local/lib/python2.7/dist-packages/ansible/playbook/__init__.py", line 348, in run
    if not self._run_play(play):
  File "/usr/local/lib/python2.7/dist-packages/ansible/playbook/__init__.py", line 789, in _run_play
    if not self._run_task(play, task, False):
  File "/usr/local/lib/python2.7/dist-packages/ansible/playbook/__init__.py", line 497, in _run_task
    results = self._run_task_internal(task, include_failed=include_failed)
  File "/usr/local/lib/python2.7/dist-packages/ansible/playbook/__init__.py", line 439, in _run_task_internal
    results = runner.run()
  File "/usr/local/lib/python2.7/dist-packages/ansible/runner/__init__.py", line 1462, in run
    p = utils.plugins.action_loader.get(self.module_name, self)
  File "/usr/local/lib/python2.7/dist-packages/ansible/utils/plugins.py", line 218, in get
    self._module_cache[path] = imp.load_source('.'.join([self.package, name]), path)
  File "/usr/local/share/kolla/ansible/action_plugins/merge_configs.py", line 21, in <module>
    from ansible.plugins.action import ActionBase
ImportError: No module named plugins.action
Command failed ansible-playbook -i /usr/local/share/kolla/ansible/inventory/all-in-one -e @/etc/kolla/globals.yml -e @/etc/kolla/passwords.yml -e CONFIG_DIR=/etc/kolla -e action=deploy /usr/local/share/kolla/ansible/site.yml

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Below are the errors with Ansible 2.1.0:
========================================

$ kolla-ansible deploy
TASK [common : Starting cron container] ****************************************
fatal: [localhost]: FAILED! => {"changed": true, "failed": true, "msg": "AttributeError(\"'NoneType' object has no attribute 'update'\",)"}
 to retry, use: --limit @/usr/local/share/kolla/ansible/site.retry

PLAY RECAP *********************************************************************
localhost : ok=15 changed=8 unreachable=0 failed=1

Command failed ansible-playbook -i /usr/local/share/kolla/ansible/inventory/all-in-one -e @/etc/kolla/globals.yml -e @/etc/kolla/passwords.yml -e CONFIG_DIR=/etc/kolla -e action=deploy /usr/local/share/kolla/ansible/site.yml

[Vikram Hosakote (vhosakot)]

Fixing this bug.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/322377

[OpenStack Infra (hudson-openstack)]

Change abandoned by Vikram Hosakote (<email address hidden>) on branch: master
Review: https://review.openstack.org/322377
Reason: Abandoning this review as https://review.openstack.org/#/c/327410/ fixed the issue.

[Vikram Hosakote (vhosakot)]

Fixed by https://review.openstack.org/#/c/327410/.