Merge branch 'develop-ascraeus' into develop

* develop-ascraeus:
  [ticket/12778] Rename the file to *.bak instead of deleting
  [ticket/12778] Automatically delete files on update

phpBB/install/install_update.php

@@ -1063,6 +1063,14 @@ class install_update extends module
 									$transfer->write_file($file_struct['filename'], $contents);
 								}
 							break;
+
+							case 'deleted':
+
+								if ($update_mode != 'download')
+								{
+									$transfer->rename($file_struct['filename'], $file_struct['filename'] . '.bak');
+								}
+							break;
 						}
 					}
 				}