Temporarily disable forcing of drawing status bar background.

Forcing status bar background drawing causes all windows to be
considered fullscreen. As a result alert dialog windows have incorrect
containing frames and aren't repositioned when IME appears.

Until a better solution is implemented for forcing drawing the status
bar, we disable it to have correct old behavior.

Bug: 26050571
Bug: 24365214
Change-Id: Ic27a394711a587fa152a238699cd19751e91a732