Remove FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET

Reasons

1) Now that QC is no longer a modal dialog, it doesn't make sense for
to use FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET. We want QC to stick around
inside the back stack.

2) FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET is deprecated. It now behaves
completely differently than it used to. It now acts the same as
FLAG_ACTIVITY_NEW_DOCUMENT.

Bug: 15693551
Change-Id: Ia22fe04d7a91876061498bf1f098755b54199704