Force clear cache on 'clear all'

Add long click to 'clear all' button in recents panel to force
clear caches, dentries and inodes

Change-Id: Iaa0ff526707be5b21bf746767f6241f4f0b6c39e

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

Conflicts:

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