Fix intermittently-failing test

[babbageclunk]

I could make it reliable for normal runs by adjusting the delay, but running it
with the race checker made that break too, so I've relaxed the exact numbers
that it checks for. Really it just needs to check that there are
multiple messages being reported - the exact counts aren't likely to be
wrong.

Running under the stress tester with the race checker on showed no failures
in 300 runs after this change.

Fixes https://bugs.launchpad.net/juju/+bug/1646504

[babbageclunk]

!!build!!

[babbageclunk]

$$merge$$

[jujubot]

Status: merge request accepted. Url: http://juju-ci.vapour.ws:8080/job/github-merge-juju

[jujubot]

Build failed: Tests failed
build url: http://juju-ci.vapour.ws:8080/job/github-merge-juju/9768

[babbageclunk]

Mongo crashed on windows. :'(

[babbageclunk]

$$merge$$

[jujubot]

Status: merge request accepted. Url: http://juju-ci.vapour.ws:8080/job/github-merge-juju

[babbageclunk]

I don't really understand what's going on with the check build. It says trusty failed with 255, but there aren't any errors in the trusty log. It also says lxd failed - it looks like it flat-out refused to bootstrap in lxd, but I can't see anything that explains why.

[jujubot]

Build failed: Tests failed
build url: http://juju-ci.vapour.ws:8080/job/github-merge-juju/9772

[babbageclunk]

$$merge$$

[jujubot]

Status: merge request accepted. Url: http://juju-ci.vapour.ws:8080/job/github-merge-juju

[jujubot]

Build failed: Tests failed
build url: http://juju-ci.vapour.ws:8080/job/github-merge-juju/9774

[babbageclunk]

$$merge$$

[jujubot]

Status: merge request accepted. Url: http://juju-ci.vapour.ws:8080/job/github-merge-juju

[jujubot]

Build failed: Tests failed
build url: http://juju-ci.vapour.ws:8080/job/github-merge-juju/9793

[babbageclunk]

The grant check has been turned off for now - it's unreliable.

[babbageclunk]

$$merge$$

[jujubot]

Status: merge request accepted. Url: http://juju-ci.vapour.ws:8080/job/github-merge-juju