Don't animate rotations when screen is off

Avoid error loops like these:

W/WindowManager( 1744): Animation repeat aborted after too many iterations
W/WindowManager( 1744): Layout repeat skipped after too many iterations
W/WindowManager( 1744): Layout repeat skipped after too many iterations
W/WindowManager( 1744): Layout repeat skipped after too many iterations
W/WindowManager( 1744): Animation repeat aborted after too many iterations
W/WindowManager( 1744): Layout repeat skipped after too many iterations

which happened mostly when the screen was turned off while a landscape
app was active.

Change-Id: Idce8fc0049758e50aaf9bc3f93aff45758ed30c1