[ticket/16857] Remove unused settings in acp_board

Add migration remove_flash_v2

PHPBB3-16857

phpBB/phpbb/db/migration/data/v400/remove_flash_v2.php

@@ -0,0 +1,39 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+namespace phpbb\db\migration\data\v400;
+
+use phpbb\db\migration\migration;
+
+class remove_flash_v2 extends migration
+{
+	public function effectively_installed()
+	{
+		return !$this->config->offsetExists('max_post_img_width');
+	}
+
+	public static function depends_on()
+	{
+		return [
+			'\phpbb\db\migration\data\v400\remove_flash',
+		];
+	}
+
+	public function update_data()
+	{
+		return [
+			['config.remove', ['max_post_img_width']],
+			['config.remove', ['max_post_img_height']],
+		];
+	}
+}