Don't track ReportDialog state in CallLogFragment.

This was implemented formerly to prevent a crash on rotation, but
this can be done by specifying that the Report fragment should be
retained in GoogleDialer.

This means that the fragment will not be retained now if the activity
is killed off by the system, but I think this should be okay since
it is a dialog.

Bug: 19949319
Change-Id: If3ebca4625fce93d9d9ce3c9bde6d92729f21c40