dirname can also return '.' for empty path

lib/connector/sabre/node.php

@@ -235,7 +235,7 @@ abstract class OC_Connector_Sabre_Node implements Sabre_DAV_INode, Sabre_DAV_IPr
 	static public function removeETagPropertyForPath($path) {
 		// remove tags from this and parent paths
 		$paths = array();
-		while ($path != '/' && $path != '') {
+		while ($path != '/' && $path != '.' && $path != '') {
 			$paths[] = $path;
 			$path = dirname($path);
 		}