[ticket/17470] Feed enable config not enforced

The 'feed_enable' config is never checked before generating the feeds. The
effective result is that feeds are always enabled, regardless of the setting.

PHPBB-17470

phpBB/phpbb/feed/controller/feed.php

@@ -123,6 +123,12 @@ class feed
 		$this->template = $twig;
 		$this->language = $language;
 		$this->phpbb_dispatcher = $phpbb_dispatcher;
+
+		// Feeds are disabled, no need to continue
+		if (!$this->config['feed_enable'])
+		{
+			$this->send_unavailable();
+		}
 	}
 
 	/**