Revert "App sidebar: put a backround to better view"

This reverts commit 9238a0fe3581401aadaa87906c311ba5e9315975.
frameworks/base: Fix change propagating issue

destroyLayer() function has been modified in kk. It is not correct
to propagate the UI corruption fix from jb to kk without considering
the new changes made in kk. This change is to make it align with
the new code in kk.

Change-Id: I34d11b230b9390fe8a989ab6f9c7d3a48d586205
Allow configuration of the default screen-off animation style

Change-Id: Ib59f8fce45c11193104682b975ff6467df8cfc15