Fix Moodle 3.1 compatibility

bookquiz/view.php

@@ -39,7 +39,7 @@ if (!$book = $DB->get_record('book', array( 'id' => $cm->instance))) {
 
 require_course_login($course, true, $cm);
 
-$context = get_context_instance(CONTEXT_MODULE, $cm->id);
+$context = game_get_context_module_instance( $cm->id);
 
 // Read chapters.
 $select = $allowedit ? "bookid = $book->id" : "bookid = $book->id AND hidden = 0";

lib.php

@@ -689,8 +689,6 @@ function game_supports($feature) {
             return true;
         case FEATURE_COMPLETION_HAS_RULES:
             return true;
-        case FEATURE_GRADE_HAS_GRADE:
-            return true;
         case FEATURE_GRADE_OUTCOMES:
             return true;
         case FEATURE_RATE: