Adjust voting rule changes again

• If kartvoterulechanges is set to Always, the third option is always the opposite gametype, even if Encore is unlocked - that will now be present on the second option instead.
  • This is both for consistancy with having Encore inaccessible on your gamedata, and a response to community feedback.
• The kartencore cvar being turned on will now be reflected in gametype rule changes from Battle to Race. This plugs one last hole in its area of effect for Race tracks.

mentioned in commit 5a878416

merged