Fix 5433466 - FU out of position during orientation change

If you turn the device from portrait to landscape mode and immediately
invoke the lockscreen, it will come up in landscape mode and switch to
the desired portrait mode within a couple of seconds.  Previously,
Face Unlock would come up in landscape mode, but its position would
not change once lockscreen corrected itself, causing Face Unlock to be
partly off the screen.

This has been fixed by checking if we are already bound to Face Unlock
when the layout is created.  If this is true, then the layout is being
created due to a change in orientation, and we stop Face Unlock, and
restart it at the new position.

This commit also adds a fix where we now use INVISIBLE for the Face
Unlock area when it is not showing instead of using GONE.  The
dimensions of the Face Unlock area is 0-by-0 when set to GONE, and we
want to avoid the possibility for the Face Unlock service being
assigned a zero area.  I'm not sure if this was ever causing problems,
but it certainly is not the intended behavior.

Also cleaned up some comments and logging.

Change-Id: I68deb49cb26dafb5c238167d0c23f0eed2cfb75a