use correct IUser in interface

lib/public/iusersession.php

@@ -52,14 +52,14 @@ interface IUserSession {
 	/**
 	 * set the currently active user
 	 *
-	 * @param \OCP\User|null $user
+	 * @param \OCP\IUser|null $user
 	 */
 	public function setUser($user);
 
 	/**
 	 * get the current active user
 	 *
-	 * @return \OCP\User
+	 * @return \OCP\IUser
 	 */
 	public function getUser();
 }