make simple-test / kv-engine-post-commit failing since 6th March

The `make simple test` we run as a post-commit job for KV-engine has started to fail (and continued to fail) since Monday 6th - see build #1299 here: http://cv.jenkins.couchbase.com/job/kv-engine-spock-post-commit/

We have this build configured to run both on each commit to memcached/ep-engine, and also every day (to ensure that we notice any changes in any of the other projects periodically). The first run to fail was one of these daily runs (and hence didn’t include any changes to memcached/ep-engine) - implying this is caused by a non KV-Engine change.

The list of changes is unfortunately quite long - see http://cv.jenkins.couchbase.com/job/kv-engine-spock-post-commit/1299/changes and the number of “ERROR” lines is high (even in the previous job 1298 which passed), but I think the first “real error” is:

2017-03-06 23:58:13 | ERROR | MainProcess | test_thread | [rest_client._http_request] http://127.0.0.1:9000/settings/rbac/users/builtin/cbadminbucket error 404 reason: unknown "User was not found.”

I’m still seeing this in the most recent failing build (http://cv.jenkins.couchbase.com/job/kv-engine-spock-post-commit/1309/label=ubuntu-1204/console).

I see a bunch of RBAC-related CBQE patches in the list - perhaps that's related?