hwui: Don't discard framebuffer on exynos4

The layers gets empty/not cleaned and redrawn on top of the preview,
causing beautiful glitch on homescreen, and drawing black instead
of transparency.

Change-Id: I633b104224c73c625f1193ee3dde41823cddc5bf
Recents : Fix clear all layout

Fixes the clear button from getting cut off due to the added
fitsSystemWindows in aosp

Change-Id: Id43a3d0640f66c1d7c587cb272bc3a6ad520628b
Merge "Recents : Fix clear all layout" into cm-10.2
SystemUI: Fix aapt warning

Change-Id: Ie7e4357de2cfe909e761ac94f1ba7a903dd397ed
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>