Currently when multiple services share a host, the
restart order is random. This is due to an unordered
dict being used to facilitate the mapping of services
to their groups, names and other options.
Based on [1], this patch implements changes to the role
to ensure that services on the same host are restarted
in the correct order when the software/config changes.
[1] https://docs.openstack.org/developer/neutron/devref/upgrade.html
Change-Id: I368b51ef37763f4163ead591d6743c4d56962ef9
2f10f75425