Use json_query whenever possible

[Jean-Philippe Evrard]

We should probably use json_query, making use of jmespath, in our playbooks/roles more, to
simplify things like:

    - ansible_local is defined
    - ansible_local.openstack_ansible is defined
    - ansible_local.openstack_ansible.glance is defined
    - ansible_local.openstack_ansible.glance.install_method is defined
    - ansible_local.openstack_ansible.glance.install_method != glance_install_method

to a single line.

It also helps getting the data into a sepecific format without being too hard to read.

Please read the jmespath [1] and json_query [2] documentation

[1]: http://jmespath.org/examples.html
[2]: http://docs.ansible.com/ansible/latest/user_guide/playbooks_filters.html#json-query-filter

[Jonathan Rosser (jrosser)]

Opinion in the #ansible IRC channel is to dissuade use of json-query in general when other mechanisms are supported.