Do not reuse a session that is not logged
Do not reuse a session that is not logged

If a session was not logged, it would still be considered a candidate for
new session objects.  Disqualify such sessions so that new session
objects after a 'logout' or similar will be fulfilled.

Change-Id: I7af11a8a300b7aedcadcec7673d6308e3b08f27d

stackforge/pyghmi,benoit-canet/pyghmi,openstack/pyghmi,openstack/pyghmi