Merge pull request #20397 from owncloud/fix-carddav-lookup

Register DAVACL plugin to provide current-user-principal

apps/dav/lib/server.php

@@ -33,6 +33,8 @@ class Server {
 		$this->server->addPlugin(new BlockLegacyClientPlugin(\OC::$server->getConfig()));
 		$this->server->addPlugin(new Plugin($authBackend, 'ownCloud'));
 
+		$this->server->addPlugin(new \Sabre\DAVACL\Plugin());
+
 		// wait with registering these until auth is handled and the filesystem is setup
 		$this->server->on('beforeMethod', function () {
 			// custom properties plugin must be the last one