SurfaceFlinger: Dont show Animation on External Display

- With this change the animation effect will not be shown on
  external display.
- It will change from portrait to landscape in one shot.
- Primary would still continue the animation effect
- set property sys.disable_ext_animation to disable animation

Change-Id: Ibd94bf166f08eeab1d504afe69230f7c6a617eb6
CRs-fixed: 453747
Merge branch 'Cyanogen/cm-10.2'