Do not save/restore whether the dashboard has finished loading.

We store whether or not the dashboard has finished loading so we know
which progress bar to show.  If we save/restore this, then when we
restore the activity, we think we have finished loading when we have
not and crash trying to show something that has not been initialized.

Fixes: 130635760
Test: Change developer option to always clear activities, open
dashboard, click home, navigate back to it.

Change-Id: Ib0526407d5210222a542ff26d6d0ac883d7b68f3