Animation Control: Fix seekbarpreference class

The custom seekbar preference listener was being instantiated in onCreate without
a method to update the default value to the user's preference... so when it was
scrolled off the screen it would reset to whatever the previous default value was.

Change-Id: I71b3da61d999870bc1e8f6f4186d0e9d5c891c13
Merge "Animation Control: Fix seekbarpreference class" into jb43