Use package instead of apt, move away from TU gds

roles/ariane/tasks/snapper.yml

@@ -1,6 +1,6 @@
 ---
 - name: snapper - install snapper
-  apt: name=snapper
+  package: name=snapper
 
 - name: snapper - create-config
   command: snapper create-config /
@@ -16,4 +16,5 @@
   lineinfile:
     dest: /etc/fstab
     line: "{{ snapper_blkid.stdout_lines[0] }} /.snapshots btrfs subvol=.snapshots 0 1"
+  when: snapper_blkid.stdout_lines is defined
   notify: snapper - reload fstab