Fix two handlings of displaytitle for workflows

classes/manager/workflow_manager.php

@@ -364,7 +364,7 @@ class workflow_manager {
     public static function create_workflow($title, $displaytitle = null) {
         $record = new \stdClass();
         $record->title = $title;
-        if ($displaytitle) {
+        if (!is_null($displaytitle)) {
             $record->displaytitle = $displaytitle;
         }
         $workflow = workflow::from_record($record);

tests/generator/lib.php

@@ -74,7 +74,7 @@ class tool_lifecycle_generator extends testing_module_generator {
         $record = new stdClass();
         $record->id = null;
         $record->title = 'myworkflow';
-        $record->title = 'random displaystring:' . random_string(10);
+        $record->displaytitle = 'random displaystring:' . random_string(10);
         $workflow = workflow::from_record($record);
         workflow_manager::insert_or_update($workflow);
         foreach ($stepnames as $subpluginname) {