Reply with UNAUTHORIZED like on APIs when login exception was thrown

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

build/integration/features/provisioning-v1.feature

@@ -687,4 +687,4 @@ Feature: provisioning
 		And assure user "user0" is disabled
 		And As an "user0"
 		When sending "GET" with exact url to "/index.php/apps/files"
-		And the HTTP status code should be "403"
+		And the HTTP status code should be "401"

index.php

@@ -55,7 +55,7 @@ try {
 		OC_Template::printExceptionErrorPage($ex, 500);
 	}
 } catch (\OC\User\LoginException $ex) {
-	OC_Template::printErrorPage($ex->getMessage(), $ex->getMessage(), 403);
+	OC_Template::printErrorPage($ex->getMessage(), $ex->getMessage(), 401);
 } catch (Exception $ex) {
 	\OC::$server->getLogger()->logException($ex, ['app' => 'index']);