privacy guard: Fix crash when uninstalling an app

 * Don't try to update the privacy guard flag while refreshing after an
   uninstall since the PM will throw an exception at us.

Change-Id: Idadb99fefc2861e871f6206b08c844dda742fa68
Handle cancellation of the 'enabling PrivacyGuard' alert box.

I noticed that the option could remain ticked but not actually enabled
if the alert box is cancelled.

Change-Id: If9a4e88641a5e4283d6ea16c17ca4461841580e3
Fix derp.

Change-Id: I2766f4c89460c967e32349be008e38b3600b7e76