MDL-39343 disable all caching in install and upgrades

This should resolve all problem on developer machines when switching branches or when restoring previous Moodle databases. It also prevents any potential problems during upgrades such as concurrent DB modification and resolves chicken egg problems in future caching upgrades.

admin/cli/install.php

@@ -127,7 +127,7 @@ if (function_exists('date_default_timezone_set') and function_exists('date_defau
 /** Used by library scripts to check they are being called by Moodle */
 define('MOODLE_INTERNAL', true);
 
-// Disables caching.. just in case.
+// Disables all caching.
 define('CACHE_DISABLE_ALL', true);
 
 // Check that PHP is of a sufficient version

admin/cli/install_database.php

@@ -29,6 +29,7 @@
  */
 
 define('CLI_SCRIPT', true);
+define('CACHE_DISABLE_ALL', true);
 
 // extra execution prevention - we can not just require config.php here
 if (isset($_SERVER['REMOTE_ADDR'])) {

admin/cli/upgrade.php

@@ -30,6 +30,7 @@
  */
 
 define('CLI_SCRIPT', true);
+define('CACHE_DISABLE_ALL', true);
 
 require(dirname(dirname(dirname(__FILE__))).'/config.php');
 require_once($CFG->libdir.'/adminlib.php');       // various admin-only functions