MDL-32881 Prevent course/view.php from being cached

This should prevent browser caching which will ensure that changes made
using the course javascript (e.g. drag/drop, show/hide) will not be 'lost'
by using the browser back button.

This reverts commit 3aaa184399.

course/lib.php

@@ -4561,9 +4561,6 @@ function include_course_ajax($course, $modules = array(), $config = null) {
         $PAGE->requires->string_for_js('pluginname', $module);
     }
 
-    // Prevent caching of this page to stop confusion when changing page after making AJAX changes
-    $PAGE->set_cacheable(false);
-
     return true;
 }
 

course/view.php

@@ -38,6 +38,9 @@
 
     $PAGE->set_url('/course/view.php', $urlparams); // Defined here to avoid notices on errors etc
 
+    // Prevent caching of this page to stop confusion when changing page after making AJAX changes
+    $PAGE->set_cacheable(false);
+
     preload_course_contexts($course->id);
     $context = context_course::instance($course->id, MUST_EXIST);
 

index.php

@@ -41,6 +41,9 @@
     $PAGE->set_url('/', $urlparams);
     $PAGE->set_course($SITE);
 
+    // Prevent caching of this page to stop confusion when changing page after making AJAX changes
+    $PAGE->set_cacheable(false);
+
     if ($CFG->forcelogin) {
         require_login();
     } else {