Fix unit tests incompatible with puppetlab-stdlib 8.0.0
Fix unit tests incompatible with puppetlab-stdlib 8.0.0

Since puppetlabs-stdlib 8.0.0, ensure_packages automatically translates
'ensure => present'  to 'ensure => installed' and that translation
breaks existing assertions in unit tests.

Change-Id: Id592ca8181caaaae448e2c965a5d61b46c1b9748

openstack/puppet-gnocchi,openstack/puppet-gnocchi