Updates to various icons:

 - updated android head in launcher icons
 - USB notifications now use a USB icon instead of the
   platform logo (ADB still uses the platform logo however)

Fixes: 138661761
Test: attach to adb; confirm that one notification uses the
      Q and one the USB logo
Test: view system apps in Settings>Apps that have no proper icon

Change-Id: Ia11736c010b4862fea8d0e73c424cfc5c51badfa