OC_App::getStorage() failed if app dir didn't exist.

lib/app.php

@@ -519,6 +519,10 @@ class OC_App{
 	public static function getStorage($appid){
 		if(OC_App::isEnabled($appid)){//sanity check
 			if(OC_User::isLoggedIn()){
+				$view = new OC_FilesystemView('/'.OC_User::getUser());
+				if(!$view->file_exists($appid)) {
+					$view->mkdir($appid);
+				}
 				return new OC_FilesystemView('/'.OC_User::getUser().'/'.$appid);
 			}else{
 				OC_Log::write('core','Can\'t get app storage, app, user not logged in',OC_Log::ERROR);