retrace: store db backups only 14 days

it consume too much disk space, be more aggresive

roles/abrt/faf-local-post/tasks/cron.yml

@@ -10,9 +10,9 @@
 
 - name: delete old database backups
   cron:
-    name: "delete database backups older than 30 days"
+    name: "delete database backups older than X days"
     user: faf
-    job: "find /srv/faf/db-backup/ -mtime +30 -type f -delete"
+    job: "find /srv/faf/db-backup/ -mtime +14 -type f -delete"
     special_time: daily
     state: present