[minor] port variables file discovery from OpenStack-Ansible

tasks/main.yml

@@ -2,9 +2,12 @@
 - name: Gather variables for each operating system
   include_vars: "{{ item }}"
   with_first_found:
-    - "{{ ansible_distribution | lower }}-{{ ansible_distribution_major_version }}.yml"
-    - "{{ ansible_distribution | lower }}.yml"
+    - "{{ ansible_distribution | lower }}-{{ ansible_distribution_version | lower }}.yml"
+    - "{{ ansible_distribution | lower }}-{{ ansible_distribution_major_version | lower }}.yml"
     - "{{ ansible_distribution_file_variety | lower }}.yml"
+    - "{{ ansible_os_family | lower }}-{{ ansible_distribution_major_version | lower }}.yml"
+    - "{{ ansible_distribution | lower }}.yml"
+    - "{{ ansible_os_family | lower }}-{{ ansible_distribution_version.split('.')[0] }}.yml"
     - "{{ ansible_os_family | lower }}.yml"
   tags:
     - node_exporter_install