Watch out for deleted user when exiting async task

Fixes a problem where the async task can take a while to execute
and in the meantime the user can be removed. On exiting the async
task and updating the UI, make sure the user hasn't been deleted.

Bug: 18411181
Change-Id: I1831f3e53084c49e27557cb7aacec78c753a611b
3 files changed