Fix animation not playing when going home while another animation is playing

When going to a new state, we cancel any currently playing animation. When
canceling the animation, we reset mState = mCurrentStableState. Thus, when
determining the duration of the new animation, we have both state == NORMAL
and mState == NORMAL, leading to a duration of 0 and therefore no animation.
Storing the fromState before canceling/resetting fixes the issue.

Change-Id: I92332deae8058c4dd41212fe7f749955ede28b1c