Fixed bug with continuously changing orientation while dreaming

If the keyguard is locked while the device is dreaming in landscape
mode, the display will be frozen. When this happens we want to continue
to use the orientation the keyguard forced since that will be the
orientation used once the display is no longer frozen vs. switching to
the orientation of the top activity.

Bug: 29542506
Change-Id: I30a8370357735dcdff336a562ca248aa9206ae29