Only show status bar blocker view if nav bar is translucent.

It's the background drawable of the translucent nav bar that makes the
blocker view necessary (as the background creates a visual 'gap' between
status bar and visual start of the nav bar), so if the nav bar isn't
translucent, there's no need for the view.

Change-Id: I684c8d24abe3d4393ae7db88fe5023aa65836164
(cherry picked from commit 4d38789a11b76692dbcbe28bd8818eed4499f50f)
Revert "Bypass the lockscreen when the hardware keyboard is slid out and security mode is 'none'"

This reverts commit 8f18dcbc7ab4d0ff53dee4b1f43b8a70a256c15a.

(cherry picked from commit d31ce8ab826d60b0fc6e72b94ef8bcb7c1c64248)