pgsql::database::populate: populate the DB only if it's empty

refs #6842

.vagrant-puppet/modules/pgsql/manifests/database/populate.pp

@@ -29,7 +29,7 @@ define pgsql::database::populate ($username, $password, $schemafile) {
   }
 
   exec { "populate-${name}-pgsql-db":
-    unless  => "psql -U ${username} -d ${name} -c \"SELECT * FROM icinga_dbversion;\" &> /dev/null",
+    onlyif  => "psql -U ${username} -d ${name} -c \"SELECT COUNT(*) FROM information_schema.tables WHERE table_schema = '${name}';\" 2>/dev/null |grep -qEe '^ *0 *$'",
     command => "sudo -u postgres psql -U ${username} -d ${name} < ${schemafile}",
     require => Pgsql::Database::Create[$name],
   }