for-each-reflog: not having $GIT_DIR/logs directory is not an error.

Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/refs.c b/refs.c
index 9e3dfb3..6387703 100644
--- a/refs.c
+++ b/refs.c
@@ -1251,7 +1251,7 @@
 		free(log);
 		closedir(dir);
 	}
-	else
+	else if (*base)
 		return errno;
 	return retval;
 }