Save bugreport info on share intent.

When a bugreport is finished, BugreportProgressService sends a
INTENT_BUGREPORT_SHARE intent containing the bugreport pid; then when
the user clicks the share notification, BugreportProgressService uses
the pid to retrieve the bugreport info.

The problem with this approach is that if the service dies before the
user clicks the notification, the bugreport won't be shared.

This change fix this scenario by saving the bugreport info in the share intent.

BUG: 26513652

Also added more logging statements.

Change-Id: Iba86d06369f843ad88194fb1dad0c8b69764df78