DO NOT MERGE: InstalledAppDetails: "Clear defaults" button now clears USB service settings

The USB service caches the preferred activity preferences for USB devices
and accessories and allows permission to access the hardware based on the
user's selection.  The "Clear defaults" button can now be used to clear
these settings.

Change-Id: If865df98214506cf2f1e35c8c6a3dbe319b125f2
Signed-off-by: Mike Lockwood <lockwood@android.com>