Merge pull request #4481 from owncloud/fix_versioning_size_check

first check if file exists before checking the files size

apps/files_versions/lib/versions.php

@@ -104,8 +104,7 @@ class Storage {
 			// we should have a source file to work with, and the file shouldn't
 			// be empty
 			$fileExists = $files_view->file_exists($filename);
-			$fileSize = $files_view->filesize($filename);
-			if ($fileExists === false || $fileSize === 0) {
+			if (!($fileExists && $files_view->filesize($filename) > 0)) {
 				return false;
 			}