There is no update available if the app didnt have a version (aka was…

… not installed)

Signed-off-by: Joas Schilling <coding@schilljs.com>

lib/private/Installer.php

@@ -389,7 +389,7 @@ public function isUpdateAvailable($appId) {
  if($app['id'] === $appId) {
  $currentVersion = OC_App::getAppVersion($appId);
  $newestVersion = $app['releases'][0]['version'];
- if (version_compare($newestVersion, $currentVersion, '>')) {
+ if ($currentVersion !== '0' && version_compare($newestVersion, $currentVersion, '>')) {
  return $newestVersion;
  } else {
  return false;