Added 404 response for missing pages

Applies to category, manufacturer, product, and information pages.

opencart/opencart#920

upload/catalog/controller/error/not_found.php

@@ -47,8 +47,6 @@ public function index() {
 
 		$this->data['button_continue'] = $this->language->get('button_continue');
 
-		$this->response->addHeader($this->request->server['SERVER_PROTOCOL'] . '/1.1 404 Not Found');
-
 		$this->data['continue'] = $this->url->link('common/home');
 
 		if (file_exists(DIR_TEMPLATE . $this->config->get('config_template') . '/template/error/not_found.tpl')) {
@@ -66,6 +64,8 @@ public function index() {
 			'common/header'
 		);
 
+		$this->response->addHeader($this->request->server['SERVER_PROTOCOL'] . '/1.1 404 Not Found');
+
 		$this->response->setOutput($this->render());
 	}
 }

upload/catalog/controller/information/information.php

@@ -86,6 +86,8 @@ public function index() {
 				'common/header'
 			);
 
+			$this->response->addHeader($this->request->server['SERVER_PROTOCOL'] . '/1.1 404 Not Found');
+
 			$this->response->setOutput($this->render());
 		}
 	}

upload/catalog/controller/product/category.php

@@ -456,6 +456,8 @@ public function index() {
 				'common/header'
 			);
 
+			$this->response->addHeader($this->request->server['SERVER_PROTOCOL'] . '/1.1 404 Not Found');
+
 			$this->response->setOutput($this->render());
 		}
 	}

upload/catalog/controller/product/manufacturer.php

@@ -423,6 +423,8 @@ public function info() {
 				'common/header'
 			);
 
+			$this->response->addHeader($this->request->server['SERVER_PROTOCOL'] . '/1.1 404 Not Found');
+
 			$this->response->setOutput($this->render());
 		}
 	}

upload/catalog/controller/product/product.php

@@ -551,6 +551,8 @@ public function index() {
 				'common/header'
 			);
 
+			$this->response->addHeader($this->request->server['SERVER_PROTOCOL'] . '/1.1 404 Not Found');
+
 			$this->response->setOutput($this->render());
 		}
 	}