Updates package/repo name in `setup.py`.
Updates package/repo name in `setup.py`.

Missed this in 516c8166646a637c7a6c4c10ccdc00766e5d9ffd.  `grep`ped for
remaining instances of `/nagios.mesos.service.check/` and `nagios`, and
didn't find anything else.

opentable/nagios-mesos-service-check