use $defaults->getName() as webdav REALM

apps/files/appinfo/remote.php

@@ -43,7 +43,8 @@ $server->httpRequest = $requestBackend;
 $server->setBaseUri($baseuri);
 
 // Load plugins
-$server->addPlugin(new Sabre_DAV_Auth_Plugin($authBackend, 'ownCloud'));
+$defaults = new OC_Defaults();
+$server->addPlugin(new Sabre_DAV_Auth_Plugin($authBackend, $defaults->getName()));
 $server->addPlugin(new Sabre_DAV_Locks_Plugin($lockBackend));
 $server->addPlugin(new Sabre_DAV_Browser_Plugin(false)); // Show something in the Browser, but no upload
 $server->addPlugin(new OC_Connector_Sabre_QuotaPlugin());