Attempt to make single-repo-change resilient to buildbot outages; put status HTML pages at workspace root

Change-Id: I8a3c01526805eac049346f1ee7b8bec273b60473
Reviewed-on: http://review.couchbase.org/34358
Reviewed-by: Chris Hillery <ceej@couchbase.com>
Tested-by: Chris Hillery <ceej@couchbase.com>