CentOS 9: Disable unit tests dependent on puppet-postgresql

The puppt-postgresql module does not support CentOS 9 yet and requires
some version parameters to be run on CentOS 9. This change disables
unit tests requiring that module, until the module supports CentOS 9.

Change-Id: Ifbdbb09a4bf036421bd2bbe0eedb8dc929423738

spec/classes/ec2api_db_postgresql_spec.rb

@@ -36,7 +36,11 @@ describe 'ec2api::db::postgresql' do
           :concat_basedir => '/var/lib/puppet/concat'
         }))
       end
-      it_behaves_like 'ec2api::db::postgresql'
+
+      # TODO(tkajinam): Remove this once puppet-postgresql supports CentOS 9
+      unless facts[:osfamily] == 'RedHat' and facts[:operatingsystemmajrelease].to_i >= 9
+        it_behaves_like 'ec2api::db::postgresql'
+      end
     end
   end