fix wrong global being written in level update routine

[ManDude]

verified in ghidra at 0x80025cf0

  if (GameCurrentZone != zone) {
    local_58 = 1;
    pzVar15 = zone->header;
    GOOLVARS.FIRST_ZONE = 0;
    pzVar16 = (zdat_header_s *)0x0;
    if (GOOLVARS.GAME_STATE == 0x600) {
      local_58 = (uint)((entityflag & 2) != 0);
    }
    if (GameCurrentZone != (zdat_entry_s *)0x0) {
    ...