multinode/upgrade: set heat::rpc_response_timeout to 600
multinode/upgrade: set heat::rpc_response_timeout to 600

Continue the work done on https://review.openstack.org/#/c/423302/

Change-Id: I931534e0ec33e131809186f74068eb479d38a0f9

openstack/tripleo-heat-templates,dprince/tripleo-heat-templates,dprince/tripleo-heat-templates,openstack/tripleo-heat-templates