Improve use of lockfile API

Remove remaining double close(2)'s.  i.e. close() before
commit_locked_index() or commit_lock_file().

Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin-reset.c

@@ -108,7 +108,6 @@ static int update_index_refresh(int fd, struct lock_file *index_lock)
 		return error("Could not read index");
 	result = refresh_cache(0) ? 1 : 0;
 	if (write_cache(fd, active_cache, active_nr) ||
-			close(fd) ||
 			commit_locked_index(index_lock))
 		return error ("Could not refresh index");
 	return result;