refs/files-backend: remove unused open mode parameter

We only need to provide a mode if we are willing to let open(2) create
the file, which is not the case here, so drop the unnecessary parameter.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 677b7e4..74c0385 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -1569,7 +1569,7 @@ static int log_ref_setup(struct files_ref_store *refs,
 			goto error;
 		}
 	} else {
-		*logfd = open(logfile, O_APPEND | O_WRONLY, 0666);
+		*logfd = open(logfile, O_APPEND | O_WRONLY);
 		if (*logfd < 0) {
 			if (errno == ENOENT || errno == EISDIR) {
 				/*