Endermen don't become friendly to the player after damaged by water

The bug

This has been occurring since 14w06a. As the enderman is hostile to a player, and they get damaged by a water block, they will teleport away, but still chase the player. This causes them to be very easy to farm, especially multiple at a time.

How to reproduce

1. Spawn/find an enderman
2. Punch it to make it attack you
3. Jump into or in front of water blocks, so the enderman runs into them
   → Notice the enderman keep attempting to get to you, and eventually die