Fix wrong nav bar animation when unlocking from AOD

Visibility of navigation bar was set too late. Set it earlier
such that it gets the right animation.

In addition to that, fixes a bug where Keyguard unlock animation
was terminated too early if there was already a scrim animation
pending.

Test: Wake-and-unlock from Aod
Bug: 63726451
Change-Id: I9a45fb27db68d56904c0fade40ea1173176beae8
(cherry picked from commit f5304ad7)