It looks like Halowaypoint removed it the gametype all together. I would put it on my fileshare but my gold subscription just ran out, if you want the gametype, I'd suggest messaging AlexJ189 or TurbTastic on Xbox Live.
Now that I think about it TurbTastic has it on his fileshare: http://www.halowaypoint.com/en-us/players/turbtastic/halo4/fileshare#!/?section=GameSettings&SearchDate=7&SortBy=2&view-select=Tile&startIndex=0&details=7b87f6e9-557c-45d3-b2c7-8df9347884b5
