Hi, I've seen the same issue in my setup based on Ubuntu 14.04 LTS, however this fixed the issue for me:

paolozar:/opt/devstack/nova$ git diff nova/objects/instance.py
diff --git a/nova/objects/instance.py b/nova/objects/instance.py
index 137f0b9..183b92f 100644
--- a/nova/objects/instance.py
+++ b/nova/objects/instance.py
@@ -21,6 +21,7 @@ from nova import notifications
 from nova import objects
 from nova.objects import base
 from nova.objects import fields
+from nova.objects import instance_info_cache
 from nova.openstack.common.gettextutils import _
 from nova.openstack.common import log as logging
 from nova.openstack.common import timeutils
paolozar:/opt/devstack/nova$

After the change, restart nova-consoleauth. Regards, Paolo