Using correct attribute of exception
Using correct attribute of exception

Currently patch (https://review.openstack.org/#/c/69837/6) was merged in
python-novaclient. New exceptions have not attribute 'code' and now we
should use http_status instead, falling back to the old attribute if
the new attribute does not exist.

Change-Id: I16e54c8e19dd93229fd7bcfe124fd4f2595f4e59
Closes-bug: #1319499

dims/heat,pratikmallya/heat,takeshineshiro/heat,gonzolino/heat,srznew/heat,rdo-management/heat,steveb/heat,cryptickp/heat,dragorosson/heat,jasondunsmore/heat,cryptickp/heat,takeshineshiro/heat,maestro-hybrid-cloud/heat,noironetworks/heat,miguelgrinberg/heat,redhat-openstack/heat,rdo-management/heat,dims/heat,srznew/heat,rh-s/heat,redhat-openstack/heat,cwolferh/heat-scratch,pshchelo/heat,openstack/heat,miguelgrinberg/heat,pshchelo/heat,dragorosson/heat,steveb/heat,rh-s/heat,maestro-hybrid-cloud/heat,openstack/heat,cwolferh/heat-scratch,pratikmallya/heat,noironetworks/heat,gonzolino/heat,jasondunsmore/heat