dont reuse etag for folders marked explicitly unscanned

Signed-off-by: Robin Appelman <robin@icewind.nl>

lib/private/Files/Cache/Scanner.php

@@ -203,7 +203,8 @@ class Scanner extends BasicEmitter implements IScanner {
 						$fileId = $cacheData['fileid'];
 						$data['fileid'] = $fileId;
 						// only reuse data if the file hasn't explicitly changed
-						if (isset($data['storage_mtime']) && isset($cacheData['storage_mtime']) && $data['storage_mtime'] === $cacheData['storage_mtime']) {
+						$mtimeUnchanged = isset($data['storage_mtime']) && isset($cacheData['storage_mtime']) && $data['storage_mtime'] === $cacheData['storage_mtime'];
+						if ($mtimeUnchanged && $cacheData['size'] !== -1) {
 							$data['mtime'] = $cacheData['mtime'];
 							if (($reuseExisting & self::REUSE_SIZE) && ($data['size'] === -1)) {
 								$data['size'] = $cacheData['size'];