Keyguard: Allow swiping up when trust managed

When the lock screen is being trust managed, the center keyguard
affordance view becomes clickable and consumes touch events, which
includes the user swiping up from the center icon to unlock.  This
patch checks if the lock screen is being trust managed and if so,
intercepts the touch events while retaining the clickability of the
center lock icon.

Change-Id: I54dd9bfdded3dbd2bf90ed1fc49dd55e5b3a7214
TICKET: CYNGNOS-2687
(cherry picked from commit 59cd5997)