We decided to delete stumbles on 400 (bad request) errors only, in that
in theory other errors, particularly 404 can be temporary and
incorrectly returned by proxies. I am trying to minimize the
possibilities of stumbles being disposed due to complaints about data
disappearing that we have no other possibilities for at this time.
Merge branch 'dev' of https://github.com/garvankeeley/MozStumbler into delete-stumbles-on-400-only
Merge pull request #1056 from garvankeeley/delete-stumbles-on-400-only

Delete stumbles on 400 (bad request) errors only