android: Clear error only when the user explicitly dismisses the dialog

android: Clear error only when the user explicitly dismisses the dialog

The previous code worked fine on rotation changes as the fragment is
destroyed and recreated causing onCreate to be called, which restores the
saved error state.  But if the user switches to a different application
and then back this is not the case.  The dialog still gets dismissed (as
we have to do so to avoid nasty exceptions on rotation changes) but since
that implicitly cleared the error state the UI was never fully restored.