Ensure we use rdo-icehouse if RDO_RELEASE is left unset
Ensure we use rdo-icehouse if RDO_RELEASE is left unset

bcrochet/instack-undercloud,eprasad/instack-undercloud,agroup/instack-undercloud,rdo-management/instack-undercloud,rdo-management/instack-undercloud,dpkshetty/instack-undercloud,dpkshetty/instack-undercloud,agroup/instack-undercloud,bcrochet/instack-undercloud,dmsimard/instack-undercloud,eprasad/instack-undercloud,dmsimard/instack-undercloud