loader: loader_lua can run command_more twice

When we quit pager, the return value 1 is returned and command_more()
interprets it as error.

when lua loader gets error from command, it will try to
interpret it once more, so we get the same file shown once more.

There is no reason why we should return error from command_more().

(cherry picked from commit 7b0d05d56dfaad4e1d5a19727e34252072913d17)