Revert "Clear Recent Apps"

This reverts commit c3d459eac127ffc37011ddd485fd771044939510.

Conflicts:
	packages/SystemUI/res/drawable-xhdpi/ic_sysbar_recent_clear.png
	packages/SystemUI/res/drawable-xhdpi/ic_sysbar_recent_clear_land.png
	packages/SystemUI/src/com/android/systemui/statusbar/BaseStatusBar.java