[automerger skipped] Revert "On device lockdown, always show the keyguard" am: eaa1291380 -s ours

am skip reason: Merged-In I9a7c5e1acadabd4484e58573331f98dba895f2a2 with SHA-1 100ae42365 is already in history. Merged-In was found from reverted change.

Reverted change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23088548

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/24762427

Change-Id: Iffe273097df8a4b91952afdc9419eafb07a46636
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>