Partly fix lockscreen blur rotation issue

This works very well when changing rotation from portrait to landscape and vice versa but doesn't work when changing rotation from landscape to landscape (90 to 270 deg) or portrait to portrait (0 to 180 deg) because we don't get notified of such changes.

Change-Id: Id4d9b4a6ce061fdb4767a8cb12dd7a8d33c99175