Add venv_tag local fact

In order to make it easier to detect the currently deployed
venv for a service, and therefore allow smarter decisions
for things like upgrading, we implement the venv tag as a
local fact.

The file used to store facts will be the same for all
OpenStack services, with each service using its own section.

Example:

"ansible_local": {
    "openstack_ansible": {
        "keystone": {
            "venv_tag": "14.2.1"
        }
    }
}

Change-Id: Icf443a93424c9eba7b68d3279ebb48ae00602808

tasks/keystone_install.yml

@@ -252,10 +252,17 @@
 
 - name: Record the need for a db sync
   ini_file:
-    dest: /etc/ansible/facts.d/keystone.fact
-    section: general
+    dest: "/etc/ansible/facts.d/openstack_ansible.fact"
+    section: keystone
     option: need_db_sync
     value: True
   when: keystone_get_venv | changed or
         keystone_venv_dir | changed or
         install_packages | changed
+
+- name: Record the venv tag deployed
+  ini_file:
+    dest: "/etc/ansible/facts.d/openstack_ansible.fact"
+    section: keystone
+    option: venv_tag
+    value: "{{ keystone_venv_tag }}"

tasks/main.yml

@@ -88,14 +88,14 @@
   when:
     - keystone_database_enabled | bool
     - inventory_hostname == ansible_play_hosts[0]
-    - ansible_local.keystone.general.need_db_sync | bool
+    - ansible_local['openstack_ansible']['keystone']['need_db_sync'] | bool
   tags:
     - keystone-config
 
 - name: Disable the need of a db sync on all nodes
   ini_file:
-    dest: /etc/ansible/facts.d/keystone.fact
-    section: general
+    dest: "/etc/ansible/facts.d/openstack_ansible.fact"
+    section: keystone
     option: need_db_sync
     value: False
   when: dbsync | succeeded