pack-refs: call fflush before fsync.

Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/builtin-pack-refs.c b/builtin-pack-refs.c
index ede4743..23d0d07 100644
--- a/builtin-pack-refs.c
+++ b/builtin-pack-refs.c
@@ -89,6 +89,7 @@
 		die("unable to create ref-pack file structure (%s)",
 		    strerror(errno));
 	for_each_ref(handle_one_ref, &cbdata);
+	fflush(cbdata.refs_file);
 	fsync(fd);
 	fclose(cbdata.refs_file);
 	if (commit_lock_file(&packed) < 0)