Remove the stats param from the puppet module

The stats param has been removed in uchiwa 0.3.0.

Please see [this commit] (https://github.com/sensu/uchiwa/commit/71880ca3ed415af3c03d618620830d13e4c6f99e#diff-04c6e90faac2675aa89e2176d2eec7d8L84)