retrace: Fix faf db backup job

The job was broken before because the backup directory
(`/srv/faf/db-backup`) might not have existed.

Also, factor out some magic values into variables.

roles/abrt/faf-post/defaults/main.yml

@@ -4,3 +4,9 @@ archive_age: '+14'
 
 # Delete deferred reports
 deferred_age: '+7'
+
+# Directory for saving FAF database backups.
+faf_backup_dir: /srv/faf/db-backup
+
+# Delete FAF database backups older than this period.
+faf_old_backup_age: '+7'

roles/abrt/faf-post/tasks/main.yml

@@ -16,6 +16,15 @@
   tags: add_repo
   loop: "{{ faf_repos }}"
 
+- name: Ensure directory for FAF database backups exists
+  file:
+    path: "{{ faf_backup_dir }}"
+    state: directory
+    owner: faf
+    group: faf
+    mode: 0750
+  when: env != 'staging'
+
 - import_tasks: cron.yml
   tags: cron