Fixes group by none defect in resource usage stats:

* Resets the inherited tenant filter queries that come
  from base class. The helper function for filter by
  meter expects a single query unlike project aggregates

Change-Id: Id9f371b09eaddd6c58d1181cbaeadf7654bbd067
Closes-Bug: #1387530
Merge "Fixes group by none defect in resource usage stats:"
Merge branch 'master' of https://github.com/openstack/horizon