Angry Wolves keep their angry texture when switching to Peaceful

When attacking a wolf and switching to peaceful difficulty, the wolf keeps it's angry texture while not acting angry.

Steps to Reproduce:
1. Attack a wolf in Survival or Adventure mode on any difficulty higher than Peaceful
2. Switch to Peaceful

Observed Results:
The wolf still appears with an angry texture for a while before reverting to it's normal texture

Expected Results:

The wolf's angry texture should instantly disappear when switching difficulties, because when attacking a wolf in Peaceful it doesn't appear angry at all.