Fix login loop for private instances

GET /login and POST /login have 2 distinct route name.

Fixes #1533

application/front/ShaarliMiddleware.php

@@ -94,7 +94,7 @@ protected function checkOpenShaarli(Request $request, Response $response, callab
             && $this->container->conf->get('privacy.force_login')
             // and the current page isn't already the login page
             // and the user is not requesting a feed (which would lead to a different content-type as expected)
-            && !in_array($next->getName(), ['login', 'atom', 'rss'], true)
+            && !in_array($next->getName(), ['login', 'processLogin', 'atom', 'rss'], true)
         ) {
             throw new UnauthorizedException();
         }