Re-fix the server global variable in Lua

I screwed up the conditions on my first attempt to fix this, since I only tested one scenario. Tested this in SP, at the main menu, and both clientside and (dedicated)serverside in MP. Everything works as intended.

src/dehacked.c

@@ -8720,7 +8720,7 @@ static inline int lib_getenum(lua_State *L)
lua_pushinteger(L, mapmusic);
return 1;
} else if (fastcmp(word,"server")) {
-		if (!playeringame[serverplayer])
+		if ((!multiplayer || !netgame) && !playeringame[serverplayer])
return 0;
LUA_PushUserdata(L, &players[serverplayer], META_PLAYER);
return 1;