MDL-57137 quiz: Create question category with specified parent category

Fix question category generator bug. Now it is possible to specify parent category of subcategory, supply only name of parent category

lib/tests/behat/behat_data_generators.php

@@ -163,7 +163,7 @@ class behat_data_generators extends behat_base {
         'question categories' => array(
             'datagenerator' => 'question_category',
             'required' => array('name', 'contextlevel', 'reference'),
-            'switchids' => array('questioncategory' => 'category')
+            'switchids' => array('questioncategory' => 'parent')
         ),
         'questions' => array(
             'datagenerator' => 'question',

question/tests/behat/question_categories.feature

@@ -40,6 +40,7 @@ Feature: A teacher can put questions in categories in the question bank
   Scenario: A question category can be edited
     When I navigate to "Categories" node in "Course administration > Question bank"
     And I click on "Edit" "link" in the "Subcategory" "list_item"
+    And the field "parent" matches value "   Default for C1"
     And I set the following fields to these values:
       | Name            | New name     |
       | Category info   | I was edited |