don't silently exit in cli-mode in case ownCloud in not yet installed

lib/base.php

@@ -214,6 +214,8 @@ class OC {
 			if (!OC::$CLI) {
 				$url = 'http://' . $_SERVER['SERVER_NAME'] . OC::$WEBROOT . '/index.php';
 				header("Location: $url");
+			} else {
+				throw new Exception("Not installed");
 			}
 			exit();
 		}