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: I4d9258e66166fdc8c4ac180fc32d41b7ec0fb2e6

spec/classes/keystone_db_postgresql_spec.rb

@@ -39,7 +39,10 @@ describe 'keystone::db::postgresql' do
         }))
       end
 
-      it_behaves_like 'keystone::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 'keystone::db::postgresql'
+      end
     end
   end
 end