MDL-79364 backup: Fix conversion for 1.9 backups.

1.9 backups used current plugin version as oldversion.
But quiz uses some hardcoded version numbers when processing
restore which is lower then current plugin number, so some quiz
logic was ignored.

See define_structure(), process_quiz_question_instance() within
restore_quiz_stepslib.php

backup/converter/moodle1/handlerlib.php

@@ -867,7 +867,9 @@ public function process_course_module($data, $raw) {
             $plugin->version = null;
             $module = $plugin;
             include($versionfile);
-            $data['version'] = $plugin->version;
+            // Have to hardcode - since quiz uses some hardcoded version numbers when restoring.
+            // This is the lowest number used minus one.
+            $data['version'] = 2011010099;
         } else {
             $data['version'] = null;
         }