Do not set cluster in maintenance mode during split stack upgrade

Do not set cluster in maintenance mode during split stack upgrade

This change noops ControllerDeployedServer{Pre,Post}Config to avoid
getting the upgrade of a split stack deployment getting stuck due
to the cluster being in maintenance mode. For reference a similar
change has been done for the regular Controller role in:
https://review.openstack.org/#/c/487313/

Change-Id: Idd393011b3c4d0d236780e11a04a59d426750de1
Closes-bug: 1725175
(cherry picked from commit 8e92d7c6db6fcae863a250f63b01a98f7a3f3340)