heat engine retrieve credentials every periodic task interval
heat engine retrieve credentials every periodic task interval

Avoid saving a session context, instead retrieve the DB stored
credentials for every periodic task trigger, and create a new
session context for each periodic event

Change-Id: I24ca70b478f06be26ca6cc74385b37d1a0cf098d
Signed-off-by: Steven Hardy <4d1810d1ff6d7f22d774341c4549c02173d2f2ab@redhat.com>

noironetworks/heat,jasondunsmore/heat,gonzolino/heat,openstack/heat,openstack/heat,rickerc/heat_audit,pratikmallya/heat,pshchelo/heat,JioCloud/heat,steveb/heat,redhat-openstack/heat,pshchelo/heat,dragorosson/heat,Triv90/Heat,jasondunsmore/heat,srznew/heat,cryptickp/heat,takeshineshiro/heat,cryptickp/heat,varunarya10/heat,ntt-sic/heat,NeCTAR-RC/heat,maestro-hybrid-cloud/heat,Triv90/Heat,JioCloud/heat,srznew/heat,takeshineshiro/heat,redhat-openstack/heat,miguelgrinberg/heat,gonzolino/heat,cwolferh/heat-scratch,NeCTAR-RC/heat,pratikmallya/heat,rh-s/heat,Triv90/Heat,cwolferh/heat-scratch,rh-s/heat,varunarya10/heat,dragorosson/heat,citrix-openstack-build/heat,maestro-hybrid-cloud/heat,rdo-management/heat,ntt-sic/heat,dims/heat,steveb/heat,noironetworks/heat,rdo-management/heat,rickerc/heat_audit,citrix-openstack-build/heat,miguelgrinberg/heat,dims/heat