[ansible] Deploy buster-backports repository only on Debian 10

Signed-off-by: Yohann D'ANELLO <ynerant@crans.org>

ansible/base.yml

@@ -7,7 +7,7 @@
       prompt: "Password of the database (leave it blank to skip database init)"
       private: yes
   vars:
-    mirror: mirror.crans.org
+    mirror: eclats.crans.org
   roles:
     - 1-apt-basic
     - 2-nk20

ansible/roles/1-apt-basic/tasks/main.yml

@@ -1,14 +1,15 @@
 ---
-- name: Add buster-backports to apt sources
+- name: Add buster-backports to apt sources if needed
   apt_repository:
     repo: deb http://{{ mirror }}/debian buster-backports main
     state: present
-  when: ansible_facts['distribution'] == "Debian"
+  when:
+    - ansible_distribution == "Debian"
+    - ansible_distribution_major_version | int == 10
 
 - name: Install note_kfet APT dependencies
   apt:
     update_cache: true
-    default_release: "{{ 'buster-backports' if ansible_facts['distribution'] == 'Debian' }}"
     install_recommends: false
     name:
       # Common tools