Write the compute upgrade script for tripleo major upgrade workflow

Write the compute upgrade script for tripleo major upgrade workflow

As part of the major upgrade workflow non-controller nodes are to
be updated by the operator, out-of-band and only after an initial
heat stack-update that invokes the upgrade of the controller nodes.

This review adds a ComputeDeliverUpgradeConfigDeployment_Step3
SoftwareDeploymentGroup to be applied only to compute nodes, and
that depends on the controllers having been upgraded after
ControllerPacemakerUpgradeConfig_Step2.

Its purpose is to deliver but not invoke the upgrade script on
compute nodes to /root/tripleo_upgrade_node.sh .

The non-controller nodes will then be upgraded later by an
operator that will run the script provided for that purpose, like
at https://review.openstack.org/#/c/284722/1 for example.

Change-Id: Ic6115fc8cf5320abfcf500112ff563bde8b88661