Don't start all services during upgrade steps

Don't start all services during upgrade steps

Currently we start all OpenStack services in step6, but puppet
already does this, and sometimes services require configuration
to account for the new version after the yum update before they
will start.

So instead of reimplementing that configuration management in
ansible, just defer starting the services until puppet has run
which will happen right after the ansible upgrade steps complete.

Note there are some DB sync operations etc that we may also be able
to remove and let puppet do those steps, but I've left those in
for now, as we know there are some actions during that phase
e.g nova cells setup, which aren't yet handled by puppet.

Change-Id: Idc8e253167a4bc74b086830cfabf28d4aab97d28