Let maintainers disable the new rotation animation

On some old phones (zeppelin, morrison, motus, hero?) the new ICS rotation
animation doesn't perform well. This patch adds a boolean property,
"persist.sys.rotationanimation", to give device maintainers and advanced
users the ability to enable/disable it.

Change-Id: I6b88eb8ec410f83c6566c07108daae442b59f79c