Use Ironic as Devstack plugin in Rally gates
Use Ironic as Devstack plugin in Rally gates

During Mitaka development cycle Ironic has completely moved
to DevStack plugin, so Rally gates testing Ironic have to be
configured accordingly.

Change-Id: I8ea548fa99d42e10298b40d2b4eb3b289f34db41

dongwenjuan/project-config,noorul/os-project-config,dongwenjuan/project-config,noorul/os-project-config,Tesora/tesora-project-config,openstack-infra/project-config,openstack-infra/project-config,Tesora/tesora-project-config