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: I07dbb985751444c12276f3ee8540d7d5dd48316e

spec/defines/keystone_resource_authtoken_spec.rb

@@ -166,7 +166,7 @@ describe 'keystone::resource::authtoken' do
 
         is_expected.to contain_package('python-memcache').with(
           :name   => platform_params[:memcache_package_name],
-          :ensure => 'present'
+          :ensure => 'installed'
         )
       end
     end