Use server container

lib/private/appframework/app.php

@@ -69,7 +69,7 @@ class App {
 			if($value['expireDate'] instanceof \DateTime) {
 				$expireDate = $value['expireDate']->getTimestamp();
 			}
-			setcookie($name, $value['value'], $expireDate, \OC::$WEBROOT, null, \OC::$server->getConfig()->getSystemValue('forcessl', false), true);
+			setcookie($name, $value['value'], $expireDate, $container->getServer()->getWebRoot(), null, $container->getServer()->getConfig()->getSystemValue('forcessl', false), true);
 		}
 
 		if(!is_null($output)) {

lib/private/server.php

@@ -631,4 +631,13 @@ class Server extends SimpleContainer implements IServerContainer {
 	function getAppManager() {
 		return $this->query('AppManager');
 	}
+
+	/**
+	 * Get the webroot
+	 *
+	 * @return string
+	 */
+	function getWebRoot() {
+		return \OC::$WEBROOT;
+	}
 }

lib/public/iservercontainer.php

@@ -298,4 +298,11 @@ interface IServerContainer {
 	 * @return \OCP\App\IAppManager
 	 */
 	function getAppManager();
+
+	/**
+	 * Get the webroot
+	 *
+	 * @return string
+	 */
+	function getWebRoot();
 }