[Bleeding] Re-add EntityShootBowEvent lost in e93a3eb3b4c5234e3e3936bc697d566a42d3b30e. Fixes BUKKIT-4214

In the 1.2 update for CraftBukkit, a missed diff resulted in Skeletons no
longer firing an EntityShootBowEvent when they shot an arrow. This commit
restores that code so that the event will once again be fired properly.