Enable WM remote occlude flag; fix occlude state issues.

The flag in KeyguardService was updated, but this one was
not, leading to some duplicate setOccluded calls.

Also, we should not be setting the keyguard occluded if
the occlusion launch animator is cancelled. Cancellations
should be ignored, if we're cancelling due to unoccluding
then we'll set occluded = false in the unocclude method.

Fixes: 228800628
Fixes: 229749961
Fixes: 230135606
Fixes: 229890065
Test: launch Camera a lot
Change-Id: I978cc051c35f84c4a967528801d3bf0f6944430b