pain code minor cleanup

[private-tristan]

About the pull request

removes some useless signal removals because the signals themselves weren't registered

Explain why it's good for the game

Testing Photographs and Procedure

while I didn't record it, I did boot up a server and made sure that devouring still killls with 200 pain, and that when i set pain to 0 it doesn't.

Changelog

no player facing changes.

[FslashN]

Looks fine. There is only one signal handler, so it does seem like the other stuff was either left over from something else or didn't get implemented in the first place.