Spawning a Shulker spawns 2.

What happens...
When you use a spawn egg for the Shulker it spawns more than one in the same space spawn with one click,

What should happen....
When you use the spawn egg only one should be spawned.

Steps to reproduce.
1. Get a shulker spawn egg.
2. Click it on the ground.
3. Hit it to see that there are actually more then one there.