In `ajax-actions.php`, remove dead code:

* In `wp_ajax_add_tag()`, `$post_type` is set and never used.
* In `wp_ajax_hidden_columns()`, `$hidden` is set twice, but only checks for the existence of `$_POST['hidden']` the first time. The two lines can be combined and work together.
* In `wp_ajax_inline_save()`, `$mode` is set and never used.
* In `wp_ajax_find_posts()`, `$searchand = $search = '';` is leftover cruft, neither variable is used. `$wpdb` does not need to be imported, it is never used.
* In `wp_ajax_wp_fullscreen_save_post()`, `$post_type` is set and never used.
* In `wp_ajax_save_attachment_order()`, `$post` is set and never used.
* In `wp_ajax_send_attachment_to_editor()`, `$title` is set and never used. 

See #27882.

Built from https://develop.svn.wordpress.org/trunk@28292


git-svn-id: http://core.svn.wordpress.org/trunk@28120 1a063a9b-81f0-0310-95a4-ce76da25c4cd
In `WP_Media_List_Table`, remove dead code:

* In `->prepare_items()`, importing `$wpdb` is unnecessary.
* In `->get_columns()`, `$taxonomies` is set twice before it is used.
* In `->display_rows()`, `$taxonomy_object` is set and never used.

See #27882.


Built from https://develop.svn.wordpress.org/trunk@28293


git-svn-id: http://core.svn.wordpress.org/trunk@28121 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Custom Header: Fix logic when a theme doesn't set `default-text-color`.

fixes #28042.
Built from https://develop.svn.wordpress.org/trunk@28294


git-svn-id: http://core.svn.wordpress.org/trunk@28122 1a063a9b-81f0-0310-95a4-ce76da25c4cd
In `WP_MS_Users_List_Table::get_views()`, remove dead code:

* `$wp_roles` doesn't need to be imported.
* `$current_role` is set and never used.

See #27882.


Built from https://develop.svn.wordpress.org/trunk@28295


git-svn-id: http://core.svn.wordpress.org/trunk@28123 1a063a9b-81f0-0310-95a4-ce76da25c4cd
In `WP_Users_List_Table::get_views()`, `$current_role` is set and never used.

See #27882.


Built from https://develop.svn.wordpress.org/trunk@28296


git-svn-id: http://core.svn.wordpress.org/trunk@28124 1a063a9b-81f0-0310-95a4-ce76da25c4cd