Bileto ignores britney problems

[Robert Bruce Park]

Just saw this:

2016-10-25T18:25:16+00:00 Running britney...
+ /var/lib/britney/britney.py --config /tmp/britney_data/2095-xenial.conf --series xenial
W: [Tue Oct 25 18:25:17 2016] - WARNING: No block hints at all, not even udeb ones!
E: [Tue Oct 25 18:28:37 2016] - Failure to fetch https://objectstorage.prodstack4-5.canonical.com/v1/AUTH_77e2ada1e7a84929a74ba3b87153c0ac/autopkgtest-xenial-ci-train-ppa-service-2095/xenial/s390x/u/unity8/20161025_182708_846c6@/result.tar: HTTP Error 502: Proxy Error
2016-10-25T18:28:42+00:00 Uploading to swift...
+ swift upload bileto-2095-excuses /tmp/britney_output/2016-10-25_18:25:01/2095_xenial_non-installable-status --object-name=2016-10-25_18:25:01/2095_xenial_non-installable-status
+ swift post bileto-2095-excuses --read-acl .r:*,.rlistings
2016-10-25T18:28:54+00:00 /var/lib/bileto/britney/fetch-indexes done.

Basically britney had a network failure but then bileto inspected the excuses as if everything was fine, instead iterate.py should notice when britney fails and abort before reporting incorrect data.