[automerger skipped] Revert "On device lockdown, always show the keyguard" am: 996896e672 -s ours am: 12913fd327 -s ours

am skip reason: Merged-In I9a7c5e1acadabd4484e58573331f98dba895f2a2 with SHA-1 b23c2d5fb6 is already in history. Merged-In was found from reverted change.

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/24757286

Change-Id: I7c70e82646c5f8c32795874c54cc7f19a929c0cf
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>