MDL-21190 Re-fixing a regression in dependency calculation

Sorry for the last commit. This should be the proper way. The problem
was with the question mark within quotes - it was not considered as a
placeholder.

lib/grade/grade_item.php

@@ -1331,16 +1331,15 @@ public function depends_on($reset_cache=false) {
 
             if ($grade_category->aggregatesubcats) {
                 // return all children excluding category items
-                $params[] = $grade_category->id;
+                $params[] = '%/' . $grade_category->id . '/%';
                 $sql = "SELECT gi.id
                           FROM {grade_items} gi
                          WHERE $gtypes
                                $outcomes_sql
                                AND gi.categoryid IN (
                                   SELECT gc.id
                                     FROM {grade_categories} gc
-                                   WHERE gc.path LIKE '%/?/%')";
-
+                                   WHERE gc.path LIKE ?)";
             } else {
                 $params[] = $grade_category->id;
                 $params[] = $grade_category->id;