Add --fail flag to zuul status backup curl

We don't want to save documents if they are errors.

Change-Id: I259d926605c56c2b2fd723c3783bb468144e063b

playbooks/roles/zuul-status-backup/tasks/main.yaml

@@ -9,7 +9,7 @@
     state: present
     user: root
     job: |
-      timeout -k 5 10 curl https://zuul.opendev.org/api/tenant/{{ tenant }}/status -o /var/lib/zuul/backup/{{ tenant }}_status_$(date +\%s).json 2>/dev/null
+      timeout -k 5 10 curl https://zuul.opendev.org/api/tenant/{{ tenant }}/status --fail -o /var/lib/zuul/backup/{{ tenant }}_status_$(date +\%s).json 2>/dev/null
 
 # Rotate backups and keep no more than 120 files -- or 2 hours worth of
 # backup if Zuul has 100% uptime.