skip data collection on / vhost to address issue #32

[tnibert]

This may not be a good candidate to merge, but it does resolve issue #32 401 returned when using plugin - even though standard Basic Auth curls work using creds, so hopefully at least contributes to a better and less hacky solution.

[coveralls]

Coverage decreased (-0.3%) to 99.693% when pulling 02769fc on tnibert:master into b6e3e59 on NYTimes:master.

[mrunge]

The change itself looks ok for me, even if it reduces coverage.

[supermitch]

This pull request means you can never get stats on "/" vhost. My understanding is that vhost prefix (when configuring RabbitMQ) is optional, so what if I want to use the default? This code would never allow me to get stats on "/"?

[tnibert]

Yes I think that is probably true. I just ran into the issue #32 in my own application and this is the quick hack that I used for it to work with my application. I submitted this pull request mostly just as a pointer like "look here, clue to the root cause."