Wolf tail height is not based on ratio of Health to maxHealth

The height of a wolf's tail which is indicating if a wolf is hurt is not based on the ration of Health to maxHealth but instead on the ration of Health to 20.

This causes wild wolves which have 8 of 8 health to display as hurt.

/summon Wolf ~ ~ ~ {Attributes:[{Name:"generic.maxHealth",Base:0.5d}],Health:0.5f}