Hello. me and my friends realized that one of suddenly got a blue revive bar when reviving a team mate. in a zombie game, after checking the leaderboards we realized that he got that after 100 revives. we all tried it out and i can confirm that when you get 100 revives on the leaderboards. you WILL get permanent quick revive in custom games. i doesn't show up as a perk but you can tell by the blue revive bar.

I hope this helped you out