Base: fix ClockView ActiveDisplay Remove Wallpaper

why no body report this bug?

this happen since AD merger into omnirom for the first time
i found this bug after using 24 time format LOL

Change-Id: I85be84914cc8210d9b0612994a4c25a5c6bfdeb6
Base: fix SystemUI because ActiveDisplay

fix http://jira.omnirom.org/browse/OMNI-708
fix http://paste.omnirom.org/view/e7039c0b
fix http://paste.omnirom.org/view/6977cb45

Change-Id: Id6688c721bd262df7824183a14fcd0aab145517e