We want the applications to handle the notification themselves if the
credentials for an account do not work (ie., if EnsureCredentials
fails). Having the daemon throw a notification is bad because:
* it does not give the user sufficient context to determine what
* background services might be calling EnsureCredentials, and these
should never lead to a notification unless it was in response to
an explicit user action
This also reverts commit cbcb0da9.