Fix misnamed function causing oddities in mountables

https://github.com/Bukkit/CraftBukkit/commit/5ac44d361574ea0585b166d4e68c5a6ef9e4d0de#diff-726d5f1fc5d364153d08e3d9df6b0cd4L1388

https://github.com/Bukkit/mc-dev/commit/c1627dc9cc7505581993eb0fa15597cb36e94244#diff-6dc1f5e1bc6540ffb609d076f0b3cf6dL1169

This was causing players to be suffocated in 2 high tunnels while on minecarts and boats to sink into solid ground.