revert desklock block_rect opacity change
revert desklock block_rect opacity change

block rects are for blocking view of the desktop. they exist for security,
preventing the desktop from being visible if a transparent lockscreen is
in use.

also split block_rects into per-zone rects for later use

ref c997077c171f6bcab895659cc3030e14d6f04026

tasn/enlightenment,tasn/enlightenment,tasn/enlightenment