Remove page manager pages from code

import_panel_pages_to_db.php

<?php

ctools_include('export');

// Get page manager definition. This could be from a
// hook_default_page_manager_pages(). It's important to remove that function
// though or page will show as "overridden".
$pages = _pages_for_import_to_db();

foreach ($pages as $page) {
  // Only store page if it already isn't in the database.
  $objects = ctools_export_load_object('page_manager_pages', 'names', array($page->name));
  if (!empty($objects[$page->name]) && $objects[$page->name]->type != 'Default') {
    continue;
  }

  $task_name = page_manager_make_task_name('page', $page->name);
  $cache = page_manager_get_page_cache($task_name);
  if (!$cache) {
    $cache = new stdClass();
  }
  page_manager_page_new_page_cache($page, $cache);
  page_manager_set_page_cache($cache);
  page_manager_save_page_cache($cache);
}