Revert ""Clear all" button on recent apps"

This reverts commit 6471aee7bec8e8d2eb179db9605d3b6a12ac48f6.

Conflicts:

	packages/SystemUI/src/com/android/systemui/recent/RecentsPanelView.java

Change-Id: I363c552afe622ef73fe7b9e093e54c0ffc683453