Do not setListener(null) onViewDetached

There's currently a race condition upon orientation changes that
causes the new view to be attached before the old view is detached.
This results in a null listener.

Fixes: 193056436
Test: Start enroll, rotate, continue enroll
Change-Id: Id6c93dc9ee847aed0fb4a7eefbb7690a5c972781
1 file changed