Do not buzzing for each progress of bugreport notification

Only alert bugreport notification at the begining and end.

Bug: 146135200
Bug: 175287931
Test: Manually changing the notification settings to default
      from silent.
Change-Id: Ie955266ad8a7a27a9dc74743e276b5e9c7a2d6fb
Merged-In: Ie955266ad8a7a27a9dc74743e276b5e9c7a2d6fb