Horses are unable to kick you off and are untamable

Normally you would click a horse with an empty hand and start riding it. It would make the smoke*ish* particles and kick you off. Then eventually you would eventually get to the point were it had the hearts effect and you could equip it with a saddle and amor (if wanted). In 15w44a (+a few snapshots prior to this) you click a horse with an empty hand and the horse just wanders and does nothing to you.